STATS Exam Questions and Answers Graded A+
Which set of characteristics will produce the smallest value for the estimated standard error? - Answer-A large sample size and a small sample variance
A researcher conducts a hypothesis test using a sample of n=20 from an unknown population. What is...
Which set of characteristics will produce the smallest value for the estimated standard
error? - Answer-A large sample size and a small sample variance
A researcher conducts a hypothesis test using a sample of n=20 from an unknown
population. What is the df value for the t statistic? - Answer-19
When n is small (less than 30), how does the shape of the t distribution compare to the
normal distribution? - Answer-It is flatter and more spread out than the normal
distribution
A sample of n=25 scores produces a t statistic of t=-2.062. If the researcher is using a
two-tailed test, which of the following is the correct statistical decision? - Answer-The
researcher must fail to reject the null hypothesis with either α = 0.05 or α = 0.01.
If other factors are held constant, what is the effect of increasing the sample size? -
Answer-It will decrease the estimated standard error and increase the likelihood of
rejecting H0
Under what circumstances can a very small treatment effect be statistically significant? -
Answer-If the sample size big and the sample variance is small
How does sample variance influence the estimated standard error and measures of
effect size such as r^2 and Cohen's d? - Answer-Larger variance increases the
standard error but decreases measures of effect size
Which of the following accurately describes a hypothesis test? - Answer-An inferential
technique that uses the data from a sample to draw inferences about a population
A hypothesis test involves a comparison which two elements? - Answer-Research
results from a sample and a hypothesis about a population
What is measured by the numerator of the z-score test statistic? - Answer-The actual
distance between a sample mean M and a population mean µ.
For a hypothesis test evaluating the effect of a treatment on a population mean, what
basic assumption is made concerning the treatment effect? - Answer-If there is a
treatment effect, it will add (or subtract) a constant to each score
, A researcher selects a sample and administers a treatment to the individuals is the
sample. If the sample is used for a hypothesis test, what does the null hypothesis (H0)
say about the treatment? - Answer-The treatment has no effect on the scores.
What is the consequence of a type II error? - Answer-Concluding that a treatment has
an effect when it really has no effect
When is there a risk of a Type I error? - Answer-Whenever H0 is rejected
The critical boundaries for a hypothesis test are z=+1.96 and -1.96. If the z-score for the
sample data is z=-1.90, what is the correct statistical decision? - Answer-Fail to reject
H0
A researcher administers a treatment to a sample of participants selected from a
population with μ=80. If a hypothesis test is used to evaluate the effect of the treatment,
which combination of factors is most likely to result in rejecting the null hypothesis? -
Answer-A sample mean much different than 80 for a large sample
A researcher expects a treatment to increase the scores for individuals in a population.
The treatment is evaluated using a one-tailed hypothesis test, and the test produces z =
+2.40. Based on this result, what is the correct statistical decision? - Answer-The
researcher should reject the null hypothesis with either a = .05 or a = .01
A researcher evaluates a treatment effect using a two-tailed hypothesis test with α= .05,
and the decision is to reject the null hypothesis. If the researcher switched to a one-
tailed test using the same sample, what decision would be made? - Answer-Definitely
reject the null hypothesis with alpha = .05 and maybe reject with alpha = .01
If an independent-measures design is being used to compare two treatment conditions,
then how many different groups of participants would be needed and how many scores
would there be for each participant? - Answer-2 groups, 1 score each
What is the position in the distribution corresponds to a z-score of z=-1.00? - Answer-
Below the mean by a distance equal to 1 standard deviation
Which of the following z-score values represents the location farthest from the mean? -
Answer-z=-2.00
For a population with μ=70 and σ=8, what is the z-score corresponding to x=82? -
Answer-+1.50
z=x-μ/σ
For a population with a standard deviation of σ=10, what is the z-score corresponding to
a score that is 5 points below the mean? - Answer-z=-0.50
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