8-5 p415 n32
Original claim: among those movies that show the use of tobacco, the mean exposure time is 2 minutes
μ = 120

The Null Hypothesis
H₀: μ = 120

The Alternate Hypothesis
H₁: μ ≠ 120

A sample of n = 28 has 27 degrees of freedom.
For a two tailed test and a level of significance, α = 0.05
t_critical = -2.052 and 2.052

Data:
x_= 102.6 and s = 121.8
t_test = (102.6-120) ⁄ (121.8 ⁄ √28) = -0.756

Because -0.756 is NOT in the Critical Region, we Fail to Reject the Null Hypothesis and the statistical analysis of the data can NOT reject the original claim.

Conclusion:
There is NOT sufficient evidence to warrant rejection of the claim that among those movies that show the use of tobacco, the mean exposure time is 2 minutes