A) The sample size.

1

• The choice between a z-test and a t-test for a
  population mean depends primarily on

A) The sample size. B) The level of
significance. C) Whether a one- or two-tailed
test is indicated. E) A z-test should
never be used.
D) Whether the given standard deviation is from
the population or the sample.
2
2) One of your peers claims that boys do better
in math classes than girls. Together you run two
independent simple random samples and calculate
the given summary statistics of the boys and the
girls for comparable math classes. In Calculus,
15 boys had a mean percentage of 82.3 with
standard deviation of 5.6 while 12 girls had a
mean percentage of 81.2 with standard deviation
of 6.7. Which of the following would be the most
appropriate test for establishing whether boys do
better in math classes than girls?

• Two sample z test for means
• C) Two sample z test for proportions
• D) Matched pair t test
• E) One sample t test for means

B) Two sample t test for means
3
3) Suppose a school district has always believed
that the mean height of their eighth grade girls
was 60 inches. Using the computer printout, which
of the following represents the calculation for
the appropriate test? Test of mu 60.00 vs mu
not 60.00 Variable n mean stdev SE
mean Heights 23 62.35 5.42 1.13
A)
B)
D)
C)
d)
E)
4
The creators of a discovery-based learning system
for statistics claim that students who are taught
using their method experience greater success
than students taught with a strictly
lecture-based method. To test the claim ,
Professor Myers decided to teach on of his
introductory courses using the discovery-based
method and the other using a lecture-based
course. Eighty introductory statistics students
were randomly assigned to one of the Professor
Myers two sections. The summary statistics for
his end-of-course assessment appear below.
s n
Lecture Method 80.6 5.2 40
Discovery-based Method 84.2 3.9 40
4)At a 0.01 significance level, test the claim
that students who learn introductory statistics
using a discovery-based approach show higher
achievement that those taught using a
lecture-based approach.
A) Reject H0, p-value lt 0.01
B) Fail to reject H0, p-value lt 0.01 C)
Reject H0, p-value gt 0.01 D) Fail to reject H0,
p-value gt 0.01 E) There is not enough information
to test the claim
5
The creators of a discovery-based learning system
for statistics claim that students who are taught
using their method experience greater success
than students taught with a strictly
lecture-based method. To test the claim ,
Professor Myers decided to teach on of his
introductory courses using the discovery-based
method and the other using a lecture-based
course. Eighty introductory statistics students
were randomly assigned to one of the Professor
Myers two sections. The summary statistics for
his end-of-course assessment appear below.
s n
Lecture Method 80.6 5.2 40
Discovery-based Method 84.2 3.9 40
5) Construct a 95 confidence interval for the
mean difference in scores of students taught
using a lecture-based method versus a
discovery-based method
B)
A)
D)
C)
E)
6
6) It is believed that using a new fertilizer
will result in a yield of 1.6 tons per acre. A
botanist carries out a two-tailed test on a field
of 64 acres. Determine the P-value if the mean
yield per acre in the sample is 1.72 tons with a
standard deviation of 0.4. What is the
conclusion at a level of significance of 10? 5?
1?

• P .0097, and so the 1.6-ton claim should be
  rejected at
• all three of these levels.
• C) P .0097, and so the 1.6 ton claim should be
  rejected at
• the 10 level but not at the 5 and 1
  levels.
• D) P .0193, and so the 1.6 ton claim should be
  rejected at
• the 1 level but not at the 10 and 5
  levels.
• E) P .0097, and so there is not enough evidence
  to reject
• the 1.6-ton claim at any of the three levels.

B) P .0193, and so the 1.6 ton claim should be
rejected at the 10 and 5 levels but
not at the 1 level.
7
7) An NCAA official claims that the average 5K
time for students trying out for college
cross-country teams is 17 minutes. A Big East
coach believes the true figure is lower among Big
East universities. He picks an SRS of 30 recruits
and calculates their mean 5K time is 16 minutes
and 52 seconds, with a standard deviation of 25
seconds. What is the p-value for the appropriate
test?
B) 0.08 C) 0.37 D) 0.42 E) 0.75
A) 0.04
8
A random sample of THS students was asked how
many credits were needed to meet the FBISD
recommended graduation requirements. The
following results in the computer output were
found TEST MU 24 VS MU NOT
24 VARIABLE N MEAN STDEV CREDITS 34 22.25 1.87

8) Which of the following is the correct null and
alternative hypotheses statements for this
situation?
A) H0 µ 24 vs. Ha µ ? 24
B) H0 µ 24 vs. Ha µ lt 24 C) H0 p 24
vs. Ha p ? 24 D) H0 µ 22.5 vs. Ha µ ?
22.5 E) H0 p 22.5 vs. Ha p ? 22.5
9
A random sample of THS students was asked how
many credits were needed to meet the FBISD
recommended graduation requirements. The
following results in the computer output were
found TEST MU 24 VS MU NOT
24 VARIABLE N MEAN STDEV CREDITS 34 22.25 1.87

9) Which of the following is the correct method
of calculating the test statistics for this
situation?
A)
B) C) D) E)
10
A random sample of THS students was asked how
many credits were needed to meet the FBISD
recommended graduation requirements. The
following results in the computer output were
found TEST MU 24 VS MU NOT
24 VARIABLE N MEAN STDEV CREDITS 34 22.25 1.87
10) The degrees of freedom for this situation
is

• 25 B) 30
• D) 34 E) 35

C) 33
11
A random sample of THS students was asked how
many credits were needed to meet the FBISD
recommended graduation requirements. The
following results in the computer output were
found TEST MU 24 VS MU NOT
24 VARIABLE N MEAN STDEV CREDITS 34 22.25 1.87
11) The p-value for this situation is
A) 0.00000004 C) 0.00000239 D) 0.99999760 E)
none of these
B) 0.00000479
12
Multiple Choice Ch 23, 24, 25 Inferences on
Means

• D 2) B
• 3) D 4) A
• 5) A 6) B
• 7) A 8) A
• 9) A 10) C
• 11) B