A study conducted in 2015 by the technology company Rovi (now TiVo) showed that the mean time spent per day browsing the video streaming service Netflix for something to watch was 19.3 minutes. Assume the standard deviation is

???? = 8.

Suppose a simple random sample of 100 visits taken this year has a sample mean of x̄ = 21.5 minutes. A social scientist is interested to know whether the mean time browsing Netflix has increased.

a. State the appropriate null and alternate hypotheses.

b. Compute the value of the test statistic.

c. State a conclusion. Use the α = 0.05 level of significance.