1. Marc wants to know if the mean age of the prison population in his city is less than 26 years. He obtains a
random sample of 25 prisoners, and finds a mean age of 24.4 years and a standard deviation of 9.2 years. At a
significance level of 0.05, what is his conclusion?
Claim
H 0 :   26 H1 :   26
t
2.44  26
 0.870
9.2
25
Not Reject the Null
There is not enough information to support the claim that prison population in his city is less than 26 years
2. A coach uses a new technique in training middle distance runners. The times for 8 different athletes to run
800 meters before and after this training are shown below.
Do the data suggest that the training helps to improve the athletes' times for the 800 meters? Test this claim
at the 5% significance level.
Claim
H 0 :  d  0 H1 :  d  0
t
1.44  0
 2.226
1.83
8
Reject the Null
There is enough information to support the claim that the training helps to improve the athletes' times for the
800 meters
3. A test of abstract reasoning is given to a random sample of students before and after they completed a
formal logic course. The results are given below. Do the data suggest that the mean score after the course
differs from the mean score before the course? Test this claim at the 5% significance level.
Claim
H 0 :  d  0 H1 :  d  0
t
3.7  0
 2.388
4.9
10
Reject the Null
There is enough information to support the claim that score after the course differ from the score before the
course
4. A manual agility test is given to applicants at a factory. The applicants place oddly shaped pegs into
corresponding holes. Below is the average number of peg that can be placed into their holes in a minute
arranged by gender.
Male
Female
Number of applicants tested
50
50
Mean
19.39
17.91
Standard deviation
2.52
3.39
At a 5% significance level test claim that there is a difference between the number of pegs each gender can
place.
Claim
H 0 : 1  2  0 H1 : 1  2  0
t
19.39  17.91
2
2.52 3.39

50
50
2
 2.478
Reject the Null
There is enough information to support the claim that there is a difference between the number of pegs each
gender can place