Question

Some students were surveyed about how much time they spent playing video games last week and their overal test average.

Find the equation of the least-squares line.

Interpret the meaning of the slope.

Interpret the meaning of the y-intercept mathematically.

State the correlation coefficient. Describe any possible correlation for the data set. Use the correlation coefficient to support your answer.

Use the equation of the least-squares line from part a to predict the test average for someone who plays 5 hours of video games a week.

Answer 1

a) The attachment shows the equation of the best-fit line. It is approximately
.. test average = 89.7 -2.93*(hours playing games)

b) The slope indicates the expected drop in test score for each hour spent playing games

c) The y-intercept is the expected test score if no hours are spent playing games.

d) The correlation coefficient is -0.92, a significant negative correlation. One might expect that hours spent playing games indicates a lack of interest in school subjects or studying, hence a likelihood that test scores will be lower.

e) The equation predicts a test score of about 75 for someone who spends 5 hours a week playing video games.