An online streaming service providing television programs claims that a 30-minute program will stream with advertisements that average 45 seconds. A consumer advocacy group is investigating to
see if this claim is true. They recorded the times of 21 randomly selected advertisements. The times
are listed below:
Time
(seconds) 45 45 43 50 50
43 50 45 49 46 48 42 46 44 52 48 45 46 50 48
The mean and standard deviation for these times are 46.67 seconds and 2.78 seconds respectively.
Do these data provide convincing evidence that the true mean advertisement length is longer than
45 seconds?