Lucy Baker Is Analyzing Demographic Characteristics of Two Television Programs $\sigma$

Multiple Choice

Lucy Baker is analyzing demographic characteristics of two television programs, American Idol (population 1) and 60 Minutes (population 2) . Previous studies indicate no difference in the ages of the two audiences. (The mean age of each audience is the same.) Her staff randomly selected 100 people from each audience, and reported the following: ₁ = 43 years and
₂ = 45 years. Assume that $\sigma$ ₁ = 5 and $\sigma$ ₂ = 8. Assuming a two-tail test and $\alpha$ =.05, the observed z value is ___.

A) -2.12
B) -2.25
C) -5.58
D) -15.38
E) -20.68