7/24/2019 Using Excel to Do Least Squares

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Slope= 0.9983 error in slope= 0.012Intercept= 0.0083 error in intercept = 0.067

Using Excel to do least squares

s an example, data points given in table (1) will be used to perform lease squ

ethod. From these data we will find the slope and the intercept of the graph of Y vs

1. Enter data in two columns, X (l/T values) first, then Y (ln(k)) values, for exam

2. Select a 2 x 2 array (2 rows and columns) anywhere on the spreadsheet.

3. In the formula pane type =Linest(B2:B10,A2:A10,true,true). Where the rang

B2:B10 determines theY values and the range A2:A10 determines the X value

4. Do CTRLSHIFT ENTER to enter the formula in the array.

5. The least squares numbers that fit to a straight line will appear as:

Slope Intercept

Std. Dev.Slope Std. Dev. Intercept

Table (1).X

y

1.0 1.1

2.0 2.0

3.0 2.9

4.0 3.9

5.0 5.0

6.0 6.1

7.0

7.0

8.0 8.1

9.0 8.9

7/24/2019 Using Excel to Do Least Squares

2/3

Slope= 0.9983 error in slope= 0.012Intercept= 0.0083 error in intercept = 0.067

Once you get the slope and intercept, select the two data columns (A and

in the example), click on INSERTon Charts, choose scatter diagram.

Then on graph that showed up, click on a point with left button and then

click right button on mouseformat trendline appearschoose linear,

then display equation and R-squared. Closer R squared is to 1, better the

linear fit.

7/24/2019 Using Excel to Do Least Squares

3/3

Slope= 0.9983 error in slope= 0.012Intercept= 0.0083 error in intercept = 0.067