A psychiatrist wondered how much a night’s sleep could affect a person’s alertness and reaction time. She collected a random sample of people and asked them (X) how many hours of sleep they got the night before and then used a simple test to determine (Y) their reaction time in seconds. The following results were obtained:
X Y
5.0……………………… 13
10.5……………………. 8
4.0 ………………………… 15
6.0 ………………………… 12
7.5………………………… 11
6.5………………………… 13
2.5………………………… 21
6.0………………………… 10
4.5 ………………………… 17
a. Draw a scatter plot of the data.
b. Calculate the regression slope and Y-intercept.
c. Draw the regression line on the scatter plot.
d. Predict the number of seconds it would take for someone who got 8.5 hours of sleep to react.
e. Find the coefficients of determination and nondetermination. What do they mean?