Question

1) State the null and alternative hypotheses (can be done in
notation format, e.g. H_{0}:_, H_{1}:_ )

2) Compute (show all work, please):

- Pooled estimate of the population variance

- Variance of each distribution of means

- Variance of the distribution of differences between means

- Standard deviation of the distribution of differences between means

3) Set the criteria for a decision (i.e. state alpha, one- or two-tailed test, degrees of freedom and the cutoff score(s)

4) Compute the test statistic
(*t _{obt}*)

5) Decide whether to retain/reject the null hypothesis &
state your conclusion in APA format (Include: the type of t-test
test used, what groups you are comparing and what you are measuring
(e.g. the I.V. and D.V.), whether it was significant or not, your
test statistic (e.g. *t*(df) = …,) and the means of time 1
and time 2; see the lecture slides for examples).

Problem 1:

A researcher wants to study the effectiveness of a new pain
management therapy program for people with chronic pain. Because it
is a new therapy, the researchers are unsure if the therapy will
increase or decrease chronic pain. Thirty-two people who experience
chronic pain agree to be in the study. The researcher randomly
picks fourteen of these volunteers to be an experimental group that
will go through the new pain management therapy. The other eighteen
volunteers are put in a control group that will go through ordinary
pain management techniques. A month after the study, each volunteer
is asked to rate the effectiveness of their pain management on a
9-point scale from 1-9 (*1 = minimal pain, 9 = maximum
pain)*. The average score for individuals in the experimental
group is (M_{1}) 3 (*S*^{2}_{1}=
3.71), while the average score for individuals in the control group
(M_{2}) 6 (*S*^{2}_{2}= 4.8). (α =
.05)

Answer #1

NULL HYPOTHESIS H0:

ALTERNATIVE HYPOTHESIS Ha:

Since P value= 0.00033

P value SMALLER THAN 0.05 THEREFORE SIGNIFICANT

DECISION: REJECT NULL HYPOTHESIS H0.

CONCLUSION: WE HAVE SUFFICIENT EVIDENCE TO CONCLUDE THAT THERE IS effectiveness of a new pain management therapy program for people with chronic pain.

1.For each situation, state the null and alternative hypotheses:
(Type "mu" for the symbol ?μ , e.g. mu >>
1 for the mean is greater than 1, mu
<< 1 for the mean is less than 1, mu not =
1 for the mean is not equal to 1. Please do not include
units such as "mm" or "$" in your answer.)
Harry thinks that prices in Caldwell are higher than the rest of
the country. He reads that the nationwide average...

For each of the following studies, state both the null and
alternative hypotheses and the decision rule, then work the
problem. Look up the critical value of t that would cut
off the tails of the distribution. Note that each study specifies
the alpha value to use and whether to use a one- or two-tailed
test. Decide whether to reject or fail to reject the null and
answer the question.
The first example does not include a sample size, I...

For each of the single sample t-tests below (problem 1-3),
please include:
1) The null and alternative hypotheses (can be written in notation
or as a sentence)
2) Calculate (show all work):
a) The estimated population variance
b) The variance of the distribution of means
c) The standard deviation of the distribution of means
3) Degrees of freedom
4) The cutoff sample score on the comparison distribution at which
the null hypothesis
should be rejected (cutoff scores)
5) The sample’s...

1. ) Suppose a
researcher is interested in the effectiveness of a new drug that is
intended to naturally increase hours of sleep for elderly patients
experiencing insomnia above 5 hours. Suppose he collects
information from a group of 64 patients, and calculates a sample
mean of 6.4 hours of sleep and a standard deviation of
s=0.8.
Write out your null and alternative
hypotheses.
Carry out the appropriate statistical test to determine
if the new treatment is effective (One sided)?...

For questions 1 through 3 state the proper t-test (one
sample, paired samples, independent samples) that should be used to
evaluate the research question: (*Just state the test)
1) A developmental psychologist wants to determine if
a recently created computer training program can increase the
working memory ability of high-school students. A sample of 40
students are given the reverse digit span test at the beginning of
the school year and then again after 4 weeks of training. Are there...

MATH 216 Final Exam Name:
__________________________________
1) Health Care Knowledge Systems reported that an insured woman
spends on average 2.3 days in the hospital for
routine childbirth with a standard deviation of 0.6 days. An
uninsured woman spends on average 1.9 days in
the hospital with a standard deviation of 0.3 days. Assume two
random samples of 16 women were used in
both samples. Can we conclude that insured women spend more time in
the hospital for routine childbirth than...

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
n1 = 4 people who received the new medication, with the
pain level for a sample of n2 = 4 people who received a
placebo. The data are as follows:...

A clinic specializing in eating disorders would like to evaluate
the effectiveness of a nutritional training program on binge eating
disorder (BED). A psychologist was hired to conduct a small study
to examine the potential effect of nutritional training on number
of binges per month. The psychologist recruited 10 patients in the
clinic to participate in a nutritional training program and 12
patients in the clinic with similar demographics who do not
participate in the nutritional program. Afterward, all participants...

1) Psychologists know that people find it easier to remember
items at the beginning and at the end of a list of items. Suppose
you think that level of education might make a difference to the
tendency to remember items in the middle of the list. You randomly
select two groups of subjects, with N = 10 in each
group. Participants in Group 1 have 12 years of
education, and members of group 2 have 20 years of education. Which...

WEEK 7, PRACTICE QUESTIONS (FROM THE BOOK)
Prerequisites
• All material presented in the Logic of Hypothesis
Testing chapter
1. An experiment is conducted to test the claim that James Bond
can taste the difference between a Martini that is shaken and one
that is stirred. What is the null hypothesis?
2. The following explanation is incorrect. What three words
should be added to make it correct?
The probability value is the probability of obtaining a
statistic as different (add...

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