Question

When it was first introduced as an antidepressant ten years ago, the average patient with a
Prozac prescription was 32 years old. In a recent random sample of 20 prescription
holders, the average age was 25 with a standard deviation s = 10 years. Use this
information to answer the following.
If you wanted to determine if Prozac users are younger now on average, which of
the following would be your null hypothesis?
A. ☐  = 25
B. ☐  = 32
C. ☐ = 7
D. ☐  < 32
E. ☐ 1-2 = 0
Which would be the logical alternative hypothesis?
A. ☐  > 25
B. ☐ 1 - 2 < 0
C. ☐ D =7
D. ☐  < 32
E. ☐   32
If you assumed that the population of Prozac users had a normally distributed age
distribution (because the sample is small), which of the following would be your critical
value for determining whether to reject or not reject the null using alpha = .10
A. ☐ 1.330
B. ☐ -1.729
C. ☐ -1.325
D. ☐ 1.328
E. ☐ -1.328
The t score you would calculate from your sample data would be
A. ☐2.236
B. ☐ .70
C. ☐ .35
D. ☐ -2.236
E. ☐ -3.13
Forget the real calculated and critical t values for the moment. For alpha=.10, what
is the probability that you would determine that Prozac users have gotten younger when
in fact they have not.
A. ☐ .10 at most
B. ☐ .90
C.☐ it depends on how much younger they are
D.☐ 1-beta
E. ☐ it is large for small samples
What kind of mistake would you be making if you were to determine that the average
age of Prozac users had not changed when in fact it had?
A. ☐ Type I
B. ☐ Type II
Again, forget the real values for a moment. What if you determined that your p
value = .08782
A. ☐You would reject the null for alpha = .05 and determine that the average age
may not have gone down
B. ☐ You accept the null for alpha =.10, and determine that the average age may not
have changed
C. ☐ You would accept the null for alpha = .10 and determine that the average has
gone down
D. ☐ You would reject the null for alpha = .05 and determine that the average age has
gone down
E. ☐ You would reject the null for alpha = .10 and determine that the average age has
gone down.
For your sample of 20, what t scores would you use to estimate a 95% confidence
interval for the current average age of Prozac users.
A. ☐ +/- 2.101
B. ☐ +/- 1.729
C.☐ +/- 1.75
D. ☐ +/- 2.093
E. ☐ none of the above

Answer 1