- The TREND function returns values along a linear trend. It fits a straight line (using the method of least squares) to the array's known_y's and known_x's. TREND returns the y-values along that line for the array of new_x's that you specify
- Trend function in Excel is a Statistical Function that computes the linear trend line based on the given linear set of data. It calculates the predictive values of Y for given array values of X and uses the least square method based on the given two data series. The Trend function in Excel returns numbers in a linear trend matching known data.
- TREND Function in Excel. TREND function is a built-in function in excel which comes under the category of Statistical function to calculate the linear trend line of known y's and know x's. TREND function uses the Least square method to find the line of best fit and to find new y-value for the given x-values
- Excel TREND function. The Excel TREND function is used to calculate a linear trend line through a given set of dependent y-values and, optionally, a set of independent x-values and return values along the trend line. Additionally, the TREND function can extend the trendline into the future to project dependent y-values for a set of new x-values
- The TREND function is an Excel Statistical function that will calculate the linear trend line to the arrays of known y and known x. The function extends a linear trend line to calculate the additional y-values for a new set of x-values. This guide will show you step-by-step how to extrapolate in Excel using this function
- The Excel TREND function calculates the linear trend line through a given set of y-values and (optionally), a given set of x-values. The function then extends the linear trendline to calculate additional y-values for a further supplied set of new x-values. The syntax of the function is: TREND (known_y's, [known_x's], [new_x's], [const]
- Returns values along a linear trend. Fits a straight line (using the method of least squares) to the arrays known_y's and known_x's. Returns the y-values along that line for the array of new_x's that you specify

Je kunt een trend vooruit of achteruit projecteren, of beide. In Excel 2003 klik je op het tabblad Opties van het dialoogvenster Trendlijn toevoegen en typ je een getal in het veld Vooruit van de groep Voorspelling om een tendens naar voren te projecteren. (Om een achterwaartse trend te projecteren, voer je een getal in het veld de veld Terug. Computes a regression line using the least squares method and produces predicted values The trend function, much like the forecast function, is used to calculate a straight line based on known X and Y values. The values of Y can be calculated for the values of X inside or outside the known range of X values. The trend here can be used to either interpolate or extrapolate the data When using the TREND function in Excel, one has to remember that it must be entered as an array formula. An array formula is entered by pressing Ctrl + Shift + Enter simultaneously. This is especially important when we want to have multiple y-values Note: when you add a trendline to an Excel chart, Excel can display the equation in a chart. This equation predicts the same future values. FORECAST.ETS. The FORECAST.ETS function in Excel 2016 or later is a great function which can detect a seasonal pattern. 1. The FORECAST.ETS function below predicts a future value using Exponential Triple Smoothing

** Additionally, Microsoft Excel allows displaying a trendline equation and R-squared value in a chart: Trendline equation is a formula that finds a line that best fits the data points**. R-squared value measures the trendline reliability - the nearer R 2 is to 1, the better the trendline fits the data Fortunately Excel has a Number of Functions and Tools that allow us to look for trends and use the data natively for forecasting purposes. There are a number of standard types of trends which can be classified as: Linear - Approximating a straight line Polynomial - Approximating a Polynomial function to a powe

TREND Function Overview. The TREND Function Calculates Y values based on a trendline for given X values. The trendline is calculated Using the least squares method based on two data series. To use the TREND Excel Worksheet Function, select a cell and type: (Notice how the formula inputs appear) TREND function Syntax and inputs: =TREND(known_ys,known_xs,new_xs,const To be honest, I'm not that familiar withe the LINEST or TREND functions. They're is a lot going on when using these, and from the documentation, they appear to be a bit unreliable (garbage in-garbage out). I think you need to understand what the Excel functions do and simply try and reproduce the results in C#. From what I can tell, no easy task Using Forecast & Trend functions in excel: Excel has a built in function to do forecasting, that is FORECAST function. In order to use forecast function, we will be using the Second Data Sheet with values from a scientific experiment. The table we will be using looks like the following: We can use the following syntax of the FORECAST function Exploring Excel Functions 8: Predicting with TREND() The TREND() function is like FORECAST() in that it calculates predictions based on known linear data. It differs in that it calculates predictions of Y for an array of X values rather than for just a single X value

A very cool feature of trendlines in Excel is the option to extend them into the future. This gives us an idea of what future values might be based on the current data trend. From the Format Trendline pane, click the Trendline Options category, and then type a value in the Forward box under Forecast The Excel FORECAST function predicts a value based on existing values along a linear trend. FORECAST calculates future value predictions using linear regression, and can be used to predict numeric values like sales, inventory, expenses, measurements, etc Excel Trend Function Another function to extrapolate data without plotting graphs is the Trend function in Excel. This statistical function is going to predict future trends according to the known values. The syntax of the Trend function

- The TREND () function is like FORECAST () in that it calculates predictions based on known linear data. It differs in that it calculates predictions of Y for an array of X values rather than for just a single X value. The syntax is as follows: =TREND (known_y_values, known_x_values, new_x_values, intercept
- A similar forecast can be made using the excel's TREND() function that takes similar arguments: TREND(known_y's, known_x's,x,[constant]) The result will be similar to what we achieved through Forecast function: Analyzing data with regression analysis: The last tool we will be discussing is Regression Analysis. In order to run Regression analysis, we need to enable analysis tool pack in excel
- Excel Function Reference. This extensive function reference list provides detailed information including syntax, arguments, return values, and examples for many of the functions used in Excel formulas. Click on headers to sort table

This wikiHow teaches you how to create a projection of a graph's data in Microsoft Excel. You can do this on both Windows and Mac computers. Open your Excel workbook. Double-click the Excel workbook document in which your data is stored Trendline in Excel is the part of all the Charts available in the Charts section under the Insert menu tab which is used to see the trend in the plotted data over any chart. This helps us to see whether there is an increase or decrease in data values. This is also helpful in seeing at which point the data is going up or down forecast.linear () It predicts or calculates values by using existing or past values. We will be predicting y by looking at x values. The linear regression function calculates this. While this function works best if there's a linear trend in your data, i.e., y is linearly dependent on x values, there's a caveat Want to master Microsoft Excel and take your work-from-home job prospects to the next level? Jump-start your career with our Premium A-to-Z Microsoft Excel Training Bundle from the new Gadget Hacks Shop and get lifetime access to more than 40 hours of Basic to Advanced instruction on functions, formula, tools, and more.. Buy Now (97% off) > Other worthwhile deals to check out

** Hi - I'm trying to use Excel's TREND function to predict a y value given a range of x,y and a given x value**. I'm doing this hundreds of times in a large spreadsheet and the ranges for both x and y change somewhat frequently Excel: General Discussion: Trend Function; cancel. Turn on suggestions. Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type

A very cool feature of trendlines in Excel is the option to extend them into the future. This gives us an idea of what future values might be based on the current data trend. From the Format Trendline pane, click the Trendline Options category, and then type a value in the Forward box under Forecast. Display the R-Squared Valu You can use the Trend () formula in 2 ways - as a normal formula, you calculate 1 point at a time. You give the known Ys and Xs, and get the trend value for 1 new point given its X value. - as an array formula, you callculate all points at a time When you add a trendline to a chart, Excel provides an option to display the trendline equation in the chart. This article describes how to create formulas that generate the trendline coefficients. You can then use these formulas to calculate predicted y values for give values of x The function then returns the coefficients of x 2 and x as well as a constant (because we chose to allow LINEST to calculate the y-intercept). The coefficients are identical to those generated by the chart trendline tool, but they are in cells now which makes them much easier to use in subsequent calculations The TREND function is applying a line to the data, so theres going to be a bump because there is a bend in the data. I returned your file with the Excel's regression functions will work on any linear function. The key skill is to coax the function to look linear

i have attempted to use the formula to the forecast function but it's not returning the correct information. would you be able to advise. Row labels are months, I would like to use the data under column labels to forecast downward trend in next 6 months ignoring the zero/blanks The Trend and Forecasting function calculates a regression line or line of best fit. When applied to a time series, it can forecast future values. This function can be used with a measure and date/time values, or with two measures where each is typically plotted along a separate chart axis

Use the TREND function to calculate the data of a trend line. This shows you the data in the worksheet so you can paste it into the chart and use other functions to control its appearance and behavior. TREND is an array function. This is a function that uses a collection of data as input and produces a collection of data as an output Excel 2007. I have, to say, 5 data sets and 5 lines on the graph. All of them have the different intervals on the x axes. I want make the trend lines for each set of data. Excel creates these 5 trend lines readily, but the lengths of all trend lines are identical and are determined by the minimal and maximal value of arguments in all 5 data sets The Forecast function is a predefined function in Excel which is categorized as a Statistical Function. It can be used as a worksheet function in Excel. Similar to all other worksheet functions, the Forecast function can also be entered as part of a formula, in a cell of a worksheet. Lets dive into some details now. Descriptio Home Tags TREND Function. Tag: TREND Function. How to Reproduce Your Excel Work Across Many Categories, Part 2... February 17, 2020. In Part 1 of this series, How to Report GL Account Groups in Excel, we explored the strategy for creating financial reports that use.. Here is how the data are set in the array just before using trend function : For subite = 1 To nb_lg - 1 y1 (subite) = Tabl1 (subite, 7) For subite2 = 1 To 6 x1 (subite, subite2) = Tabl1 (subite, subite2) Next subite2 Next subite For subite2 = 1 To 6 x2 (subite2) = Tabl2 (ite, subite2) Next subite2 y2 (ite) = Application.WorksheetFunction.Trend.

* Function Description The Excel Forecast function predicts a future point on a linear trend line fitted to a supplied set of x- and y- values*. The syntax of the function is: FORECAST (x, known_y's, known_x's The FORECAST and TREND function give the exact same result. When you add a trendline to an Excel chart, Excel can display the equation in a chart (see below). You can use this equation to calculate future sales. Explanation: Excel uses the method of least squares to find a line that best fits the points **Excel** Linear Interpolation. Linear interpolation in **excel** means forecasting or guessing the upcoming next value of any certain variable given on the current data, here we create a straight line which connects two values and we estimate the future value through it, in **excel** we use forecast **function** and a lookup **function** to do a linear interpolation

* Excel has many great tools for sales forecasting*. Knowing the following functions is helpful to get your data in order. Check out the following handy forecasting functions. Function What It Does CORREL The worksheet version of the Data Analysis add-in's Correlation tool. The difference is that CORREL recalculates when the input data changes, and the [ Advanced Excel Statistical - TREND Function - The TREND function returns values along a linear trend. Fits a straight line (using the method of least squares) to the arrays known_y's and known_x's. Return I was asked to use Excel to extrapolate the growth of used capacity for drive size on a server. Not really knowing too much about statistical functions, I thought I'd try to educate myself. I found the Trend function in Excel and it seemed to do what I want. But then I was reading about the Growth Trend - where you select a number of cells and then drag the fill handle it it just fills in.

- When analyzing trends, you are better able to predict future trends and various indicators, but also better explain past occurrences. Here are three great ways to keep track of trends using Excel. 1. Mini line graph. One way is to simply use trend lines in the cell next to the data
- Feb 25 2017 Calculate Average Trends in Excel. Excel Formulas; average, excel, forecast, projections, trends, year on year; 3 Comments; Helping some students at Columbia with an Excel exercise and though I'd post the exercise here since it brings up some interesting concepts around calculate trends and changes in values
- The calculation of the linear forecast is quite easy because Excel helps us with different functions. I will show three different ways you can calculate your trendline. The first option you have is to use the FORECAST function. The FORECAST function will return the Y value corresponding to a given X value, given your original observations
- The FORECAST.LINEAR function is categorized under Excel Statistical functions. It will calculate or predict for us a future value by using existing values. In financial modeling, the FORECAST.LINEAR function can be useful in calculating the statistical value of a forecast made. For example, if we know th
- This Excel tutorial explains how to use the Excel SLOPE function with syntax and examples. The Microsoft Excel SLOPE function returns the slope of a regression line based on the data points identified by known_y_values and known_x_values
- Using the -SQRT(B^2-4AC) option, yields a result which is compatible with the trendline forecast on the Excel chart. However, when I use the TREND function to extrapolate the dataset as a 2nd order polynomial, the result is limited to the value which is produced when solving the quadratic equation with the +SQRT(B^2-4AC) formulation

Created attachment 36200 TREND patch This is an incomplete implementation of the Excel TREND function. Most cases do work already, but some don't work yet due to the way the math library handles multiple linear regression. Specifically, cases where there are more x variables than the sample size and some cases where there are duplicate x values fail Computes the trend along the forecast time of the ensemble mean by least square fitting, and the associated error interval. Trend () also provides the time series of the detrended ensemble mean forecasts. The confidence interval relies on a student-T distribution.. Btw, I was actually googling to confirm if the Excel's TREND() formula only do linear function. Though I didn't find my answer from your post, its good to know about the LINEST() formula. Thanks

- [FONT=Arial]I am trying to trend some data and need some help or other alternatives to solve my issue. I have tried TREND with INDIRECT and get the incorrect answer. In columns M and N the highlighted cells in yellow are the correct answers.[/FONT
- Trend Function â Back to Course Content In this video we show how to use multiple regression and the TREND array function to predict US Presidential elections. These are the two files needed to follow along to this video: TREND FUNCTION START TREND FUNCTION FINISH Previous Lesson Back t
- Excel makes adding a trend line to a chart quite simple. To add a trendline, select the data series and do one of the following: Select a data series, Excel displays the Chart Tools, adding the Design and Format tabs
- Sample Workbook to TREND function in Excel Time series trendline analysis Project a trend into the future Trend formula with multiple sets of x-values Trendline chart and equation The workbook shows how to do trend analysis in Excel by using the TREND function and a few other ways. Ablebits.com TREND function and other ways to do trend analysis.
- The trend describes the general tendency of the data which could be increasing or decreasing or stable. For instance, at the time of demonetization, we observed a decreasing trend for stock prices. Or over the years, we have seen an increase in the number of sales of smartphones. A trend often depicts the long term movement of the series

- In Excel, you can extend your data and project the data trend into the future or past using the features of Trendline. In this example, you want to forecast sales for the next 6 periods. Follow the steps below to understand how to forecast data trends. STEP 1: Double click on the trendline to open the Format Trendline pane
- In Excel I could have a table as follows: Month Usage Trend 1 55 56.29 2 57 56.77 3 56 57.26 4 62 57.74 5 59 58.23 6 56 58.71 The 3rd column (Trend) is calculated using the Trend function...quite easy in Excel
- Excel 2016 introduced a number of new forecasting functions based on the triple exponential smoothing (i.e. Holt-Winter) approach. This is also called ETS forecasting for error, trend, seasonal.. Excel 2016 Functions: In the following, R1 contains the observed data values (also called historical values) and R2 contains the time values.For Example 2 of Holt-Winters Forecasting, R1 is range M4.
- y = detrend(x,n) removes the nth-degree polynomial trend.For example, when n = 0, detrend removes the mean value from x.When n = 1, detrend removes the linear trend, which is equivalent to the previous syntax. When n = 2, detrend removes the quadratic trend

Excel trendline is a great way to visualize the general trend in your data.. In total, there are 6 different types of trendlines in Excel you can use depending on the type of data you have.. Furthermore, you can add more than 1 type of trendline! Fortunately, it's quite easy to do Reliant on the accuracy of your estimate of the trend; No measure of how accurately your estimate fits the data; Next: In the next post we will look at using excel functions to automatically estimate lines of best fit and other excel functions to aid in estimation of non-linear functions. Further Readings. Are You Trendy (Part 2) Are You Trendy. Now the Trend-y Excel Fun Begins. Using your snazzy new equation, you can model out exactly how much you should upscale production. I used the formula on units ranging from 1 to 200,000 and modeled out the revenue. Approx 107,000 units is the magic number

- Sales Trend Analysis looks at historical revenue data to identify patterns, used extensively in budgeting and forecasting. It is a useful method to detect short-term changes in revenue growth an
- Trend Charts are very good visualization technique in my earlier post Trend Chart in Tableau. I have used Tableau for the Trend Chart. In this tutorial we'll learn how to make Trend Charts in Excel and use of Alt Key Codes and Paste Special in Excel. Step 1. Creating the formula and assigning the trend arrows(up or down) Here we have two colum
- The following question was put to me last week: In the following table there are month on month totals (perhaps for sales). I would like to show the red, yellow and green trend arrows against each value to show the change against the previous month's value. Using the same logic I need to show the same coloured arrows for the same data expressed as a percentage change
- The Excel trend function is certainly not the right candidate! Thanks in advance. Reply. Charles says: March 14, 2016 at 10:59 pm Glad you liked the referenced webpage. As you probably know, you can add a linear trendline to an Excel scatter chart
- Now I assumed that I can Use RGP() (German Excel version of the LINEST() function in English) but I get totally different results compared to the result of a trendline i put into the diagram (excel can show the formulas of trendlines in diagrams). What I did is: Column U: All Y Values (10 values) Column V: All X Values (10) Column W: All Y^2 Value
- Trend Function. You cannot basically sum percentage growth prices, especially when they are compounded. I wish to calculate traffic development after 6 months of SEO. At the end of 6 month we want to show a 25% increase in traffic
- Trend Analysis Excel Template Free Sample Trend Analysis Excel Template excel word pdf doc xls blank Tips: Placement of the text is an important element. Be sure to break your line up the way it should be read, For balance and proportion, ensure the thickness of the elements in accordance with the weight of the font & Take in the natural composition of your background image for text placement.

For trend analysis you can use the Trend function and to visualize and calculate trends, Excel charts can show trends and the equation for the trend. You can calculate the accuracy of the trend or Excel can provide you with this information in a chart. The Trend function will only return a accurate result if you work with linear data There are several pre-made functions built into Excel that allow you to predict values based on previous results, and the TREND function is one example. Unlike other forecasting functions - the FORECAST function, for example - the TREND function is an Array function. This means that it must be used in a specific way The TREND function can also forecast data for future time periods. Use the TREND function to forecast out as many periods as you think are valid. In general, for most business situations where you are forecasting months, you should probably only forecast two or three months ahead Trendline in Excel on different charts. Trendline is applied for illustrating price change trends. The element of technical analysis is a geometrical representation of the mean values of the analyzed indicator. Here's how to add a trendline to a chart in Excel. ï» With that in mind, Excel offers several different ways to calculate trendlines on a graph, as shown below. All those can be handled by LINEST as well! Refer to the quick reference above for how to generate coefficients for different trend/regression types. In conclusion, I hope you've found this reference useful

The Trend function combines both steps in a single function, and returns exactly the same end result: = Trend(Y_1, X_1, x) The Linest and Trend functions will also work with non-linear data: In this example the Y values in the Linest function have been replaced with their natural logarithm (using the LN function) In this course, he shows how to use Excel's data-analysis toolsâincluding charts, formulas, and functionsâto create accurate and insightful forecasts. Learn how to display Validating a multiple-regression equation using the TREND function. This movie is locked and only viewable to logged-in members. Embed the preview of this course. I am looking for a sas function that generates a trend/forecast for these values (for e.g.: 12/2014 trend: 3.255.000). While searching the web I found a function called proc timeseries, but unfortunately this function is not available in SAS 9.1.3. Does anyone know a function or solution for my problem? Thanks in advance and best regards.

Linear Regression. Forecasting in Excel can be done using various formulas. One of the most commonly used formulas is the FORECAST.LINEAR for Excel 2016, and FORECAST for earlier versions. Although Excel still supports the FORECAST function, if you have 2016 or later, we recommend updating your formulas to prevent any issues in case of a function deprecation Let me start out by saying that Excel's Forecast Function is not a complete inventory forecasting system. Forecasting in inventory management generally involves removing noise from demand, then calculating and incorporating trends, seasonality, and events The TREND function can be added another way by inserting it into a cell from the statistical functions list. By using this method, Excel will walk you through the creation of the function by allow you to enter function variables into fields with explanations for every variable entry

Linear Trend function in Excel Mohamad January 17, 2013 04:17. Follow. In this video, we'll demonstrate the use of NumXL's NxTrend to conduct a linear trend and back-test it. Video script. Scene 1: Welcome to the time series trend analysis tutorial. In this video we'll. ** I used TREND and LINEST to create a stright line fit in data table (instead of chart) in excel**, are these 2 functions also available in Spotfire as calculated column?I used TREND and LINEST to create a stright line fit in data table (instead of chart) in excel, are these 2 functions also available in Spotfire as calculated column

Interpolation using the FORECAST function. In the 2016 version of Excel, there were lots of new statistical functions added. To make room for these new functions, FORECAST has been replaced with the FORECAST.LINEAR function. Though FORECAST still remains at the moment for the purpose of backward compatibility with Excel 2013 and before The Excel FORECAST function uses the least squares or linear regression method to forecast future values. For example, sales, stock requirements, trends etc. Note : In Excel 2016 this function has been replaced by the FORECAST.LINEAR function as part of the new library of forecasting functions ** The RAND function generates a decimal number between zero and 1**. So, you might get output like this from RAND() in three cells: 0.54739314 0.919767722 0.633760119 Dates in Excel are defined as simple numbers, where.. This Excel tutorial explains how to use the Excel INTERCEPT function with syntax and examples. The Microsoft Excel INTERCEPT function returns the y-axis intersection point of a line using x-axis values and y-axis values

It turns out that Excel really wants to return two numbers from the function. Here's the trick: Select two cells that are side by side. Type the function in the first cell. After you type the closing parenthesis, press Ctrl+Shift+Enter. Excel returns both the slope and the y-intercept. The results appear in 2 cells. Add a Prediction column Discover Pivot Tables - Excel's most powerful feature and also least known. Pivot Table calendar. Sum stock portfolio. Time sheet by project. Analyze trends. Split values. Disable auto col width. Normalize data [VBA] Auto populate a worksheet. Drop-down - source. Follow hyperlinks. Count unique distinct. Auto refresh. Count uniq. dist. By using these functions together, we can extract the values of x1, y1, x2, and y2 we need for the interpolation. Linear Interpolation in Excel. Let's take a look at how to perform this analysis on some real data. The table below lists air density as a function of temperature in 20 degree Celsius increments In most cases, you may get multiple sets of experiment data. You can show these sets of data in a scatter chart simultaneously, and then use an amazing chart tool - Add Trend Lines to Multiple Series provided by Kutools for Excel - to add the best fit line/curve and formula in Excel. Kutools for Excel - Includes more than 300 handy tools for Excel

- In Excel 2016, new forecasting sheet functions and one-click forecasting helps you to explain the data and understand future trends. Let's take a closer look at some of the capabilities that come with these new features, including how to detect seasonality, understand the level of confidence in the prediction, and create the forecast in one-click
- Hello OzGrid Friends,I am trying to use VBA to find a value on a trendline. I have been unable to call the TREND function from Excel, and I can't see what I'm doing wrong. I'm using the following line of code:(Code, 1 line)I keep getting Runtime erro
- Hi, I have to calculate forecast values similar to excel FORECAST() & TREND() functions: I've attached QVW file with above data (actual) & my attempt - 5942
- In Getting value on Y axis by putting X axis value on the Mr
**Excel**forum, someone wanted to know how to find in-between values of a**function**, given some known data points. The approach, of course, is to interpolate values given the known points on either side of the value you need. Interpolation requires some simple algebra - I am trying to write a Trend function in excel 2003 VB When i use this Trend function it works: Application.Trend([A2:C2]) However, I need to have a couple other commands in that function. When I try to use this command: Application.Trend([A2:C2]4,True) it errors on me it i am trying to set it as long and if i am trying to put it as a value in the cell it puts in #VALUE! , however i can.
- You can even create your own functions (UDFs). However, you can also utilize many of Excel's functions in VBA by using Application.WorksheetFunction. How to Use Worksheet Functions in VBA. To access an Excel function in VBA add Application.WorksheetFunction in front of the function that you wish to call

MS Excel Business Inventory Analysis Template via (xltemplates.org) Bill Brown Google via (plus.google.com) Free Sample,Example & Format Trend Analysis Excel Template ywsjl Instant Customer Data Analysis using Excel worked example The via (bioteams.com) Excel Dashboards for Tracking Sales Performance 32 Examples of via (chandoo.org) Trend Analysis Template in Excel Format Project Management. Solved: Hi, Can we bring the FORECAST() and TREND() functions capability in Qlik Sense ?? Thanks in Advance Regards BB - 144136 The TREND function works well on horizontal as well as vertical data range. Unlike some other function, there is no need to use the TRANSPOSE with this function. See the above same data below but aligned horizontally. Here also the TREND formula works flawlessly without any additional data formatting Having reviewed basic functions, cell references, and date and time functions, we now dive into some of the more advanced features of Microsoft Excel. We present methods to solve classic problems in finance, sales reports, shipping costs, and statistics The Excel FORECAST.LINEAR function is new in Excel 2016 and forms part of the new suite of forecasting functions. The FORECAST.LINEAR function uses the least squares or linear regression method to forecast future values based on historical figures