Experimental Design & Practices 1 (Linear Regression)

Question 1

What does the line of best fit mean?

Answer 1

-Best fit means difference between the actual y values and the predicted y values (values of the fitted line) is a minimum

-Positive differences off-set negative ones

Question 2

What technique would you use to minimise error

Answer 2

-To minimise error use the Least Square Technique. You square the difference of the y values and find the sum of all the squared differences up to the nth term.

Question 3

R^2 is a measure of what

Answer 3

-R^2 is a measure of the quality of the fit to the data, the closer it is to 1 the better. It has a specific equation (1- a fraction of 2 sums)

-R^2 is not the only measure of quality

Question 4

To create a graph with a linear regression line…

Answer 4

highlight your values in your table, click insert and select scatter plot, right click on a data point, choose trend line and add R^2 value.

Click data analysis, choose regression, this will include standard error.

Question 5

Standard error is a measure of…

Answer 5

Standard error is a measure of dispersion of the sampling distribution for specific coefficient, very similar to standard deviation. It can be used to work out the T statistic