Question

A researcher wants to evaluate the pain relief effectiveness of
a new medication for chronic pain sufferers. Using a pain scale
from 0 to 10 (where 0 = no pain at all, and 10 = the most pain you
can imagine), she compares the pain level for a sample of
n_{1} = 4 people who received the new medication, with the
pain level for a sample of n_{2} = 4 people who received a
placebo. The data are as follows:

Medication | Placebo | |

7 | 6 | |

4 | 7 | |

6 | 9 | |

4 | 7 | |

(a) Identify the Independent Variable (IV):

Pain level

People taking placebo

People taking medication

Medication type

(b) Identify the Dependent Variable (DV):

Pain level

People taking placebo

People taking medication

Medication type

(c) What is the null hypothesis (H_{0}) for a two-tailed
test?

*μ*_{1} - *μ*_{2} ≥ 0

*μ*_{1} - *μ*_{2} ≤ 0

*μ*_{1} -
*μ*_{2} = 0

*μ*_{1} - *μ*_{2} ≠ 0

(d) What is the alternative hypothesis (H_{1}) for a
two-tailed test?

*μ*_{1} - *μ*_{2} > 0

*μ*_{1} - *μ*_{2} < 0

*μ*_{1} -
*μ*_{2} = 0

*μ*_{1} - *μ*_{2} ≠ 0

(e) Compute *df* for an independent *t* test.

*df* =

(f) Use the *t* distribution table in Appendix B to
determine the critical value of *t* for a two-tailed test at
the 0.01 level of significance. (Use 3 decimal places.)

*t*-critical = ±

(g) Calculate the Means for each group:

*M*_{1} =

*M*_{2} =

(h) Calculate the Sum of Squares (*SS*) for each group: (Use
3 decimal places.)

*SS*_{1} =

*SS*_{2} =

(i) Calculate the Pooled Variance: (Use 3 decimal places.)

*S _{P}*

(j) Calculate the Standard Error of the Difference in the Means:
(Use 3 decimal places.)

*S _{(M1-M2)}* =

(k) Calculate the *t* statistic: (Use 3 decimal places.)

*t* =

(l) What decision should be made about the null hypopthesis
(H_{o})?

Fail to reject the null hypothesis, there is not a significant difference between the placebo and medication groups.

Reject the null hypothesis, there is not a significant difference between the placebo and medication groups.

Reject the null hypothesis, there is a significant difference between the placebo and medication groups.

Fail to reject the null hypothesis, there is a significant difference between the placebo and medication groups.

(m) Calculate the estimated Cohen's *d* and
*r*^{2} to measure effect size for this study. (Use
3 decimal places.)

*d* =

*r*^{2} =

(n) How would the results be presented in the literature?

The participants taking the pain medication reported less pain
(*M* = 5.25, *SD* = 1.500) than the participants
taking the placebo (*M* = 7.25, *SD* = 1.258). This
difference was significant, *t*(7) = -2.043, *p* <
0.01.

The participants taking the pain medication reported less pain
(*M* = 5.25, *SD* = 1.500) than the participants
taking the placebo (*M* = 7.25, *SD* = 1.258). This
difference was not significant, *t*(7) = -2.043, *p*
> 0.01.

The participants taking the pain medication reported
less pain (*M* = 5.25, *SD* = 1.500) than the
participants taking the placebo (*M* = 7.25, *SD* =
1.258). This difference was not significant, *t*(6) =
-2.043, *p* > 0.01.

The participants taking the pain medication reported less pain
(*M* = 5.25, *SD* = 1.500) than the participants
taking the placebo (*M* = 7.25, *SD* = 1.258). This
difference was significant, *t*(6) = -2.043, *p* <
0.01.

Answer #1

A clinical trial is run to evaluate the efficacy of a new
medication to relieve pain in patients undergoing total knee
replacement surgery. In the trial, patients are randomly assigned
to receive either the new medication or the standard medication.
After receiving the assigned medication, patients are asked to
report their pain on a scale of 0-100 with higher scores indicative
of more pain. Data on the primary outcome are shown below. Sample
Size Mean Pain Score Standard Deviation of...

A researcher is using a repeated measures design to evaluate the
effectiveness of a pain-relief patch designed for lower back pain.
Prior to testing the patch, each of n = 5 patients rates the
current level of back pain on a scale from 1 to 10. After wearing
the patch for 90 minutes, a second pain rating is recorded. Please
calculate the appropriate hypothesis test using all FOUR STEPS
(hint: Use a two-tailed with an α = .05). Show all...

Researchers wants to know if taking the herbal supplement St.
John's Wort will affect depression. First, they measure the
depression level of a sample of n = 4 depressed people
(Pre-Test Scores). Then after a week of taking St. John's Wort,
they again measure the sample's depression levels (Post-Test
Scores). Note that high scores on the depression measure indicate
more depression, whereas low scores indicate less
depression.
Participant
Pre-Test
Scores
Post-Test
Scores
A
9
6
B
12
5
C
13...

A group of researchers wants to examine whether taking multiple
practice quizzes improve scores on tests. They compare the exam
scores for a sample of n1 = 12 students who
took multiple practice quizzes with the test scores of a sample of
n2 = 10 students who did not do any practice
quizzes. Results of the study revealed that the practice quiz group
had M1 = 95, SS1 = 52. The
no quiz group had M2 = 92,
SS2 =...

In the journal Mental Retardation, an article reported the
results of a peer tutoring program to help mildly mentally retarded
children learn to read. In the experiment, the mildly retarded
children were randomly divided into two groups: the experimental
group received peer tutoring along with regular instruction, and
the control group received regular instruction with no peer
tutoring. There were n1 = n2 = 36 children in each group. The
Gates-MacGintie Reading Test was given to both groups before
instruction...

A pharmaceutical company is testing a new drug to increase
memorization ability. It takes a sample of individuals and splits
them randomly into two groups: group 1 takes the drug, group 2
takes a placebo. After the drug regimen is completed, all members
of the study are given a test for memorization ability with higher
scores representing a better ability to memorize. Those 30
participants on the drug had an average test score of 32.74 (SD =
4.858) while those...

Consider the computer output below.
Two-Sample T-Test and CI
Sample
N
Mean
StDev
SE Mean
1
15
54.79
2.13
0.55
2
20
58.60
5.28
1.2
Difference = μ1-μ2
Estimate for difference: –3.91
95% upper bound for difference: ?
T-test of difference = 0 (vs <): T-value = -2.93
P-value = ?
DF = ?
(a) Fill in the missing values. Use lower and upper bounds for
the P-value. Suppose that the hypotheses are H0: μ1-μ2=0 versus H1:
μ1-μ2<0.
Enter your...

A researcher would like to evaluate the effect of a new cold
medication on reaction time. It is known that under regular
circumstances the distribution of reaction times is normal with µ =
200. A sample of n = 9 participants is obtained. Each
person is given the new cold medication, and 1 hour later reaction
time is measured for each individual. The average reaction time for
this sample is M = 206 with SS = 648. The
researcher would...

A random sample of
n1 = 49
measurements from a population with population standard
deviation
σ1 = 5
had a sample mean of
x1 = 8.
An independent random sample of
n2 = 64
measurements from a second population with population standard
deviation
σ2 = 6
had a sample mean of
x2 = 11.
Test the claim that the population means are different. Use
level of significance 0.01.(a) Check Requirements: What
distribution does the sample test statistic follow? Explain.
The...

A random sample of
n1 = 49
measurements from a population with population standard
deviation
σ1 = 3
had a sample mean of
x1 = 13.
An independent random sample of
n2 = 64
measurements from a second population with population standard
deviation
σ2 = 4
had a sample mean of
x2 = 15.
Test the claim that the population means are different. Use
level of significance 0.01.
(a) Check Requirements: What distribution does the sample test
statistic follow? Explain....

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 6 minutes ago

asked 8 minutes ago

asked 21 minutes ago

asked 29 minutes ago

asked 49 minutes ago

asked 55 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago