38 terms

ch 6,7, & 8

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A researcher records the following times (in seconds) that it took a group of mice to complete a maze: 23 ± 4.1 (M ± SD). The top 10% of mice finishing with the fastest times will be placed in a "maze bright" group. What is the cutoff time to be placed in this group?

a) 17.75 seconds
b) 28.25 seconds
c) faster than 16 seconds
d) There is not enough information to answer this question.
b
A researcher finds that the average preschool-aged child drinks two cups of milk per day. Assuming these data are normally distributed, the z score for the average cups per day in this example is

a) less than 0
b) greater than 0
c) exactly equal to 0
d) There is not enough information to answer this question.
c
A researcher determines that students are active about 60 ± 12 (M ± SD) minutes per day. Assuming these data are normally distributed, what is the z score for students being active 48 minutes per week?

a) 1.0
b) −1.0
c) 0
d) There is not enough information to answer this question.
b
A counselor records the number of disagreements (per session) among couples during group counseling sessions. If the number of disagreements is distributed normally as 4.4 ± 0.4 (M ± SD) disagreements, then what proportion of couples disagree at least 4 times during each counseling session?

a) 0.3413
b) 0.1587
c) 0.8413
d) The probability is not listed in the unit normal table.
c
The standard normal distribution is normally distributed with a mean of ____ and a variance of ____.

a) 0; 1
b) 1; 0
c) any value; any positive value
d) any positive value; any value
a
What is the z score for scores in the top and bottom 2.5%?

a) ±1.96
b) 1.96
c) 0.0124
d) ±0.675
a
A researcher records the following response times to a visual stimulus: 23 ± 3.1 (M ± SD) seconds. Assuming these data are normally distributed, what is the probability that participants responded in 20 seconds or less?

a) 0.1660
b) 0.3340
c) 0.6660
d) The probability is not listed in the unit normal table.
a
Most behavioral phenomena are believed to approximate the normal distribution.

a) True
b) False
a
The following samples were selected by two researchers. Which is associated with a smaller standard error of the mean?
Researcher A: n = 25, μ = 5, σ = 7
Researcher B: n = 25, μ = 32, σ = 7

a) Researcher A
b) Researcher B
c) They both have the same standard error.
c
The following samples were selected by two researchers. Which is associated with a smaller standard error of the mean?
Researcher A: n = 36, μ = 12, σ = 9
Researcher B: n = 36, μ = 12, σ = 6

a) Researcher A
b) Researcher B
c) They both have the same standard error.
b
Two researchers select a sample for a population with a mean of 12.4 and a standard deviation of 9. Researcher A selects a sample of 30 participants. Researcher B selects a sample of 40 participants. Which sample is associated with a smaller standard error?

a) Researcher A's, because the sample size was smaller.
b) Researcher B's, because the sample size was smaller.
c) Researcher A's, because the sample size was larger.
d) Researcher B's, because the sample size was larger.
d
The mean of the sampling distribution of sample means is

a) equal to the population mean
b) equal to the population variance
c) all of the above
d) none of the above
a
A researcher selects two samples of 25 participants each. In the first sample the population mean was 32 and the variance was 8. In this second sample, the population mean was 4 and the variance was 8. Which sample will be associated with a larger standard error of the mean?

a) Sample 1
b) Sample 2
c) None, both samples will have the same value for standard error.
d) There is not enough information to answer this question.
c
A statistics instructor wants to measure the effectiveness of his teaching skills in a class of 114 students
(N = 114).

He selects students by waiting at the door to the classroom prior to his lecture and pulling aside every third student to give him or her a questionnaire.

(a) Is this sample design an example of random sampling? Explain.

a) Yes, because each student has an equal chance of being selected, and each student is replaced before selecting another student.
b) No, because each student is not selected at random, and each student is not replaced before selecting another student.


(b) Assuming that all students attend his class that day, how many students will he select to complete the questionnaire?

_________ students
b; 38
A distribution of all sample means or sample variances that could be obtained in samples of a given size from the same population is called

a) a conditional procedure
b) a sampling distribution
c) sampling without replacement
d) random sampling
b
A sampling distribution is a distribution of all sample means or sample variances that could be obtained in samples of a given size from the same population.

a) True
b) False
a
A sample mean is not always equal to a population mean.

a) True
b) False
a
A researcher selects a sample of 121 participants from a population with a mean of 32 and a standard deviation of 22. What is the standard error of the mean?

a) 32
b) 2.0
c) 0.5
d) There is not enough information to answer this question.
b
A researcher selects a sample of 16 participants from a population with a variance of 4. What is the standard error of the mean?

a) less than 1
b) equal to 1
c) greater than 1
d) There is not enough information to answer this question.
a
What does the standard error measure?

a) Standard error measures the distance from the maximum value of the sample means to the minimum value of the sample means.
b) Standard error measures the dispersion or deviation of sample values from the sample mean.
c) Standard error measures the distance that sample mean values can be expected to deviate from the value of the population mean.
d) Standard error measures the most frequently occurring amount that the sample means deviate from the population mean.
c
A researcher obtains
z = −6.45.
What is the decision for a one-tailed test, upper-tail critical, at a 0.05 level of significance?

a) to reject the null hypothesis
b) to retain the null hypothesis
c) It depends on the sample size.
d) There is not enough information to make a decision.
b
Which of the following is not one of the four steps to hypothesis testing?

a) state the hypotheses
b) evaluate the plan
c) set the criteria for a decision
d) compute the test statistic
b
Based on the effect size conventions,
d = 0.60
is a

a) small effect size
b) medium effect size
c) large effect size
b
Increasing sample size will

a) Increase the alpha level.
b) Increase the likelihood of committing a Type I error.
c) Increase the power of the decision.
d) All of the above.
c
For each p value stated below, what is the decision for each if
α = 0.05?
What is the decision for each if
α = 0.01?

For
p = 0.2000,
what is the decision if α = 0.05?

a) Retain the null hypothesis.
b) Reject the null hypothesis.
a
For each p value stated below, what is the decision for each if
α = 0.05?
What is the decision for each if
α = 0.01?
For
p = 0.2000,
what is the decision if α = 0.01?
a) Retain the null hypothesis.
b) Reject the null hypothesis.
a
For each p value stated below, what is the decision for each if
α = 0.05?
What is the decision for each if
α = 0.01?
For
p = 0.0250,
what is the decision if α = 0.05?
a) Retain the null hypothesis.
b) Reject the null hypothesis.
b
For each p value stated below, what is the decision for each if
α = 0.05?
What is the decision for each if
α = 0.01?
For
p = 0.0250,
what is the decision if α = 0.01?
a) Retain the null hypothesis.
b) Reject the null hypothesis.
a
For each p value stated below, what is the decision for each if
α = 0.05?
What is the decision for each if
α = 0.01?
For
p = 0.0020,
what is the decision if α = 0.05?
a) Retain the null hypothesis.
b) Reject the null hypothesis.
b
For each p value stated below, what is the decision for each if
α = 0.05?
What is the decision for each if
α = 0.01?
For
p = 0.0020,
what is the decision if α = 0.01?
a) Retain the null hypothesis.
b) Reject the null hypothesis.
b
For each p value stated below, what is the decision for each if
α = 0.05?
What is the decision for each if
α = 0.01?
For
p = 0.0001,
what is the decision if α = 0.05?
a) Retain the null hypothesis.
b) Reject the null hypothesis.
b
For each p value stated below, what is the decision for each if
α = 0.05?
What is the decision for each if
α = 0.01?
For
p = 0.0001,
what is the decision if α = 0.01?
a) Retain the null hypothesis.
b) Reject the null hypothesis.
b
A researcher conducts two studies. Each study was a one-sample z test. Both studies placed the rejection region in both tails and measured the same sample mean. The alpha level in Study 1 was larger than the alpha level used in Study 2. Which study is associated with greater power to detect an effect?

a) Study 1
b) Study 2
c) They are associated with the same level of power.
a
A researcher reports the following result for a one-sample z test at a 0.05 level of significance:
z = 1.88,

p = 0.06 (d = 0.25).
Is this result significant?

a) Yes, the decision is to reject the null hypothesis.
b) Yes, because the effect size is large.
c) No, the decision is to retain the null hypothesis.
d) No, because the effect size is small.
c
The probability of committing a Type I error is stated by ________; the probability for committing a Type II error is stated by ________.

a) beta; alpha
b) alpha; beta
c) a p value; a p value
d) the power; the power
b
Given the following values:
μ = 6.0,
M = 7.6,
n = 36,
σ = 6,
conduct a one-sample z test at a 0.05 level of significance. For a one-tailed test, upper-tail critical, what is the decision?

a) to reject the null hypothesis
b) to retain the null hypothesis
c) There is not enough information since the sample size is not given.
b
In hypothesis testing, a researcher's decision

a) is based on a probability
b) depends on the level of significance for a hypothesis test
c) can be to retain or reject the null hypothesis
d) all of the above
d
The null hypothesis and alternative hypotheses are statements about parameters in the population.

a) True
b) False
a