A recent national survey found that high school students wat

A recent national survey found that high school students watched an average (mean) of 7.5 DVDs per month with a population standard deviation of 0.60 hour. The distribution of DVDs watched per month follows the normal distribution. A random sample of 42 college students revealed that the mean number of DVDs watched last month was 6.80. At the 0.05 significance level, can we conclude that college students watch fewer DVDs a month than high school students?

Compute the value of the test statistic:

Solution

The test statistic is

Z=(xbar-mu)/(s/vn)

=(6.8-7.5)/(0.6/sqrt(42))

=-7.56