Using a word document, please answer each question by showing the work. If SPSS, Excel, or STAT Disk is used to determine the answer, please copy and paste the results into the word document with the appropriate question. Please cite all work using APA guidelines if applicable.CHAPTER 15 Review Questions*15.7
An educational psychologist wants to check the claim that
regular physicalexercise impr
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Using a word document, please answer each question by showing the work. If SPSS, Excel, or STAT Disk is used to determine the answer, please copy and paste the results into the word document with the appropriate question. Please cite all work using APA guidelines if applicable.

**CHAPTER 15 Review Questions**

***15.7
**An educational psychologist wants to check the claim that
regular physical

exercise improves
academic achievement. To control for academic aptitude,

pairs of college
students with similar GPAs are randomly assigned to either

a treatment group
that attends daily exercise classes or a control group. At

the end of the
experiment, the following GPAs are reported for the seven

pairs of participants:

**(a) **Using
*t*, test the null hypothesis at the .01 level of significance.

**(b) **Specify
the *p *-value for this test result.

**(c) **If
appropriate (because the test result is statistically significant), use

Cohen’s *d *to
estimate the effect size.

**(d) **How might this test result be reported in the literature?

**15.8
**A school psychologist wishes to determine whether a new
antismoking film

actually reduces the
daily consumption of cigarettes by teenage smokers.

The mean daily
cigarette consumption is calculated for each of eight teenage

smokers during the
month *before *and the month *after *the film presentation,

with the following results:

(**Note: **When
deciding on the form of the alternative hypothesis,

*H *1,
remember that a positive difference score ( *D *5 *X *1 2 *X *2 )
reflects a

*decline
*in cigarette consumption.)

**(a) **Using
*t *, test the null hypothesis at the .05 level of significance.

**(b) **Specify
the *p *-value for this test result.

**(c) **If
appropriate (because the null hypothesis was rejected), construct a 95

percent confidence
interval for the true population mean for all difference

scores, and use
Cohen’s *d *to obtain a standardized estimate of the effect

size. Interpret these
results.

**(d) **What might be done to improve the design of this experiment?

***15.10
**In a classic study, which predates the existence of the EPO
drug, Melvin

Williams of Old
Dominion University actually injected extra oxygen-bearing

red cells into the
subjects’ bloodstream just prior to a treadmill test. Twelve

long-distance runners
were tested in 5-mile runs on treadmills. Essentially,

two running times
were obtained for each athlete, once in the treatment or

blood-doped condition
after the injection of two pints of blood and once in

the placebo control
or non-blood-doped condition after the injection of a

comparable amount of
a harmless red saline solution. The presentation of

the treatment and
control conditions was counterbalanced, with half of the

subjects unknowingly
receiving the treatment first, then the control, and

the other half
receiving the conditions in reverse order.

Since
the difference scores, as reported in the *New York Times, *on

May 4, 1980, are
calculated by subtracting blood-doped running times

from control running
times, a positive mean difference signifies that the

treatment has a
facilitative effect, that is, the athletes’ running times are

shorter when blood
doped. The 12 athletes had a mean difference running

time, D*¯* of 51.33
seconds with a standard deviation, ***S D (please see image below)*, of 66.33 seconds**. ** ****(***this is how the S D should be written in this sentence* *and there should be a*** ***line over the D (of 51.33)*

** **

**(a) **Test
the null hypothesis at the .05 level of significance.

**(b) **Specify
the *p *-value for this result.

**(c) **Would
you have arrived at the same decision about the null hypothesis if

the difference scores
had been reversed by subtracting the control times

from the blood-doped times?

**(d) **If
appropriate, construct and interpret a 95 percent confidence interval

for the true effect
of blood doping.

**(e )
**Calculate and interpret Cohen’s *d *for these results.

**(f) **How
might this result be reported in the literature?

**(g) **Why
is it important to counterbalance the presentation of blood-doped

and control
conditions?

**(h) **Comment
on the wisdom of testing each subject twice—once under the

blood-doped condition
and once under the control condition—during a

single 24-hour
period. (Williams actually used much longer intervals in

his study.)

**15.14
**In Table 7.4 on page 173, all ten top hitters in the major
league baseball in

2011 had lower
batting averages in 2012, supporting regression toward the

mean. Treating
averages as whole numbers (without decimal points) and

subtracting their
batting averages for 2012 from those for 2011 (so that

positive difference
scores support regression toward the mean), we have

the following ten
difference scores: 14, 39, 61, 60, 13, 21, 50, 93, 16, 61.

**(a) **Test
the null hypothesis (that the hypothetical population mean difference

equals zero for all
sets of top ten hitters over the years) at the .05 level of

significance.

**(b) **Find
the *p *-value.

**(c) **Construct
a 95% confidence interval.

**(d) **Calculate
Cohen’s *d*.

**(e) **How might these findings be reported?

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