Question

Find the linear regression equation (line of best fit), determine the correlation, and then make a prediction.

1. The table below gives the amount of time students in a class studied for a test and their test scores.

Graph the data on a scatter plot, find the line of best fit, and write the equation for the line you draw.

Hours Studied	1	0	3	1.5	2.75	1	0.5	2
Test Score	78	75	90	89	97	85	81	80

Linear Regression Equation: ____________________

Correlation Coefficient (r): _________

Type of Correlation: ______________________

Is the correlation strong? Explain

Using the linear regression equation predict

a students test score if they studied for 4 hours.

Answer 1

X: Hours Studied

Y: Test score

We can solve this question using excel.

First, enter data into excel.

Click on Data -------> Data Analysis --------> Regression ------->

Input

Input Y Range : select y values

Input X Range :select values of x.

Output Range: select an empty cell

---------> ok

We get

Linear Regression equation: y = 76.4064 + 5.4254*x

Correlation coefficient (r) = 0.7860

Type of correlation: There is positive correlation between two variables.

There is a moderate-strong correlation.

The predicted students test score for x = 4 is y = 76.4064 + 5.4254*4 = 98.108