1. We reject the null hypothesis only when:
a. our sample mean is larger than the population mean.
b. the p value associated with our test statistic is greater than
the significance level of the test
we have chosen.
c. our sample mean is smaller than the population mean.
d. the p value associated with our test statistic is smaller than
the significance level of the test
we have chosen.
2. In a study of simulated juror decision making, researchers
investigated whether there was a
relationship between the type of verdict and the type of abuse
experienced by the defendant. Half
of the participants read a 12 page summary of a case where, a
physically abused woman, shot
and killed her husband, while the other half of the participants
read a 12 page summary of a case
where, an emotionally abused woman, shot and killed her husband.
Participants were then asked
to assign a verdict (not guilty or guilty). After analysis, the
researchers failed to reject the null
hypothesis. What conclusions can they make?
a. There are more not guilty verdicts, when there is physical
abuse.
b. There are more not guilty verdicts, when there is emotional
abuse.
c. There is a no relationship between verdicts and type of
abuse.
d. There is a relationship between verdicts and type of abuse.
3. The p value is the:
a. probability with which a test statistic would occur if the
research hypothesis were true.
b. probability with which a test statistic would occur if the null
hypothesis were true.
c. cutoff probability at which a test statistic is considered
extreme.
d. probability with which a test statistic would occur if both the
null and research hypothesis
were false.
Please use the following information to answer questions 4, 5, 6,
and 7:
Researchers conducted a study to assess the notion that women talk
more than men by
comparing the number of words uttered, per day, by each sex.
Volunteer participants wore
inconspicuous recording devices that recorded their daily word
usage. Based on the study
results (contained in the following table), is there any validity
to the notion that women talk
more than men do?
Number of Participants Mean Standard Deviation
Women 5 16,200.80 1779.45
Men 5 15,989.40 2229.85
4. What is the appropriate hypothesis test?
a. z-test
b. t-test for matched pairs
c. t-test for independent samples
d. chi square test for independence
5. What are the null and alternative hypotheses?
a. Ho:?1=?2; Ha:?1<?2
b. Ho:?1??2=0; Ha:?1??2?0
c. Ho:?1??2=0; Ha:?1??2<0
d. Ho:?1??2=0; Ha:?1??2>0
6. What is the value of the test statistic?
a. .166
b. .264
c. .118
d. 7.46
7. The p-value obtained for this study was .8727. What do these
results tell us?
a. the data provide sufficient evidence to reject H0; therefore, we
conclude that there are no
differences in number of words uttered daily by women and the
number of words uttered
daily by men.
b. the data provide sufficient evidence to reject H0; therefore, we
conclude that the number
of words uttered daily by women is greater than the number of words
uttered daily by
men.
c. the data do not provide sufficient evidence to reject H0;
therefore, we conclude that there
are no difference in number of words uttered daily by women and the
number of words
uttered daily by men.
d. the data do not provide sufficient evidence to reject H0;
therefore, we conclude that the
number of words uttered daily by women is greater than the number
of words uttered daily
by men.
Please use the following information to answer questions 8, 9, 10,
11, and 12:
It is known that the population mean for the verbal section of the
SAT is 500, with a standard
deviation of 100. In 2006, a sample of 100 students taking the SAT,
whose family income was less
than $10,000, had a verbal SAT score of 429. Perform a one-tailed
hypothesis test to determine
whether the group, whose family income was less than $10,000,
scored significantly lower on
average than the population.
8. What is the appropriate hypothesis test?
a. t-test for matched pairs
b. z-test
c. t-test for independent samples
d. chi square test for independence
9. What are the null and alternative hypotheses?
a. H0:?=?0; Ha:?<?0
b. H0:?=?0; Ha:?>?0
c. H0:?=?0; Ha:???0
d. None of these are correct
10. What is the value of the test statistic?
a. -.71
b. .71
c. -7.1
d. +7.1
11. What is the p-value for the test statistic (based on rounded
values)?
a. .2389
b. .7611
c. 1.000
d. .0000
12. Using the significance level of .05, do the results lead to
rejection of the null hypothesis?
Please describe what the results tell us about mean verbal SAT
scores for those with a
family income is less than $10,000.
a. Yes, reject the null hypothesis. The mean Verbal SAT score for
students, whose family
income was less than $10,000, is not significantly lower than then
the average Verbal SAT
score for the population.
b. Yes, reject the null hypothesis. The mean Verbal SAT score for
students, whose family
income was less that $10,000, is significantly lower than then the
average Verbal SAT
score for the population.
c. No, do not reject the null hypothesis. The mean Verbal SAT score
for students, whose
family income was less than $10,000, is not significantly lower
than then the average
Verbal SAT score for the population.
d. No, do not reject the null hypothesis. The mean Verbal SAT score
for students, whose
family income was less than $10,000, is significantly lower than
then the average Verbal
SAT score for the population.
13. Researchers investigated the effects of encoding conditions on
subsequent memory for a list
of words. Participants were assigned to one of three encoding
conditions: 1) saw list of nouns
they were asked to remember (word alone condition), 2) list of
words was accompanied by a
picture (word + picture condition), or 3) list of words was
accompanied by sound effects
matching the object (sound-effects condition). A week later,
researchers measured the
proportion of words that participants got correct on a word
recognition test. The researchers
analyzed the data using an ANOVA, which resulted in the following
table:
Analysis of Variance for Encoding Conditions
DF SS MS F P
Group 2 .177 .089 13.129 0.000
Error 9 .061 .007
Total 11 .238
Using the above table, we can conclude that:
a. the data provide strong evidence that subsequent memory for
words are related to
encoding conditions.
b. the data provide strong evidence that subsequent memory for
words are related to
encoding conditions in the following way: The proportion of words
remembered by people
who are in the sound-effects condition is higher than the
proportion of words remembered
by people who are in the word + picture condition, which in turn is
higher than the
proportion of words remembered by people who are in word alone
condition.
c. the data provide strong evidence that the three word proportion
scores (representing the
three encoding conditions) are all equal.
d. the data do not provide sufficient evidence that subsequent
memory for words is related to
encoding conditions.
14. A researcher, who was interested in gender differences,
conducted a study to determine
whether there is a difference between the weekly allowances given
to 10 year old boys and
the weekly allowances given to 10 year old girls. The researcher
asked thirty 10 year old
boys and thirty 10 year old girls, the amount they received for
their weekly allowance. What
would be the appropriate hypothesis testing technique to analyze
the data from this study?
a. t-test for two independent samples
b. t-test for matched pairs
c. z-test for population mean
d. correlation
15. Valium is a drug that is used in the treatment of anxiety. A
researcher was interested in
determining the effect of Valium on the motor performance of rats.
Thirty rats were randomly
assigned to one of the following three groups: 1) low dose of
Valium, 2) high dose of Valium,
or 3) placebo (saline water). After injection with the assigned
substance, the rats were
immediately placed in a Skinner box and the number of bar presses
made in 5 minutes was
recorded by the researcher. What hypothesis testing technique
should the researcher use
to analyze the data from this study?
a. t-test for two independent samples
b. z-test for population mean
c. Chi square test for independence
d. ANOVA
16. A psychologist, who studies sleep and memory, is interested in
determining whether
shortterm memory is affected by sleep loss. A group of participants
is administered a
shortterm memory test at 9 am on Day 1 and again at 9 am on Day 2,
after the participants
were kept awake all night. What hypothesis testing technique should
the researcher use to
determine whether sleep loss affects shortterm memory?
a. t-test for two independent samples
b. Chi square test for independence
c. t-test for matched pairs
d. correlation
17. A light bulb manufacturer advertises that its 75 watt bulbs
have an average life of 1000 hours.
A consumer product advocacy group wanted to determine whether or
not this is false
advertising. The advocacy group bought 30 bulbs and burned them
until they failed. They
found that the light bulbs burned an average of 1217 hours with a
standard deviation of
216.93 hours. What hypothesis testing technique should be used to
determine whether or not
the average life time of the sample of light bulbs is different
from the advertised life time?
a. t-test for population mean
b. z-test for population mean
c. t-test for two independent samples
d. t-test for matched pairs
18. A resident of Hoboken, New Jersey, wondered whether the average
cost of a parking ticket in
Hoboken, differed from that in New Jersey cities as a whole. Public
records from city parking
utilities across the state revealed that in 2007, the average cost
of a parking ticket in the state
was $45, with a standard deviation of $11. In that same year, the
average cost of a sample of
15 parking tickets in Hoboken totaled $57. What hypothesis test
should the resident use to
analyze the data?
a. t-test for two independent samples
b. z-test for population mean
c. t-test for matched pairs
d. t-test for population mean
19. A professor is interested in determining whether assigning
mandatory homework affects
students
Statistical hypotheses testing: Hypotheses testing is used to make inferences about the population based on the sample data. The hypotheses test consists of null hypothesis and alternative hypothesis.
Null hypothesis: The null hypothesis states that there is no difference in the test, which is denoted by . Moreover, the sign of null hypothesis is equal , greater than or equal and less than or equal .
Alternative hypothesis: The hypothesis that differs from the is called alternative hypothesis. This signifies that there is a significant difference in the test. The sign of alternative hypothesis is less than , greater than , or not equal .
P-value method approach: If the probability value less than or equal to the level of the significance, then reject the null hypothesis. Moreover, the probability of obtaining the value from the sample test statistic which is extremely small that can be found in the sample data by assumption of null hypothesis is being true.
Rejection rule based on p-value:
If then reject null hypothesis.
Rejection rule for critical value method:
If , then reject the null hypothesis .
(1)
The rejection rule states that, the null hypothesis is rejected if p-value is less than the level of significance and the null hypothesis is not rejected if the p-value is greater than the level of significance.
(2)
The experiment is conducted to test whether there is a relationship between the type of verdict and the type of abuse experienced by the defendant.
State the hypotheses.
Null hypothesis:
There is no relationship between the type of verdict and the type of abuse.
Alternative hypothesis:
There is relationship between the type of verdict and the type of abuse.
From that the given information, the researcher failed to reject the null hypothesis. This implies that there is no relationship between the type of verdict and the type of abuse.
(3)
The probability of getting the value of the statistic that is as extreme as the observed statistic considering the null hypothesis is true is called as p-value.
Ans: Part 1The p-value associated with out test statistic is smaller than the significance level of the test we have chosen.
1. We reject the null hypothesis only when: a. our sample mean is larger than the population mean. b. the p value asso...
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r joint null hypothesis test statistic comes . If ou out to be greater than the relevant critical value, do we reject or fail to reject the joint null hypothesis? S&W Chapter 9 -Assessing Studies Based on Multiple Regression 21. In the S&W format, list the five sources of bias in the estimated coefficients outlined in the text and describe each with a few words. r joint null hypothesis test statistic comes . If ou out to be greater than...
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