Question: You work as a data analyst for a retail company with multiple stores. You want to find the most typical milk brand customers purchase at each store to optimize inventory. Which measure would you use?

Answer Choices:
Mean
Median
Mode
All of the above

Answer: Mode

Question: The mean and median are equal for a distribution of scores. What is most likely the distribution’s shape?

Answer Choices:
Negatively skewed
Positively skewed
Impossible to determine the shape
Symmetrical

Answer: Symmetrical

Question: For a negatively skewed distribution with a mode of X=15 and a mean of X=10, what is the most likely value for the median?

Answer Choices:
Greater than 15
Less than 10
Between 10 and 15
Exactly 12.5

Answer: Between 10 and 15

Question: In a survey conducted at a school, students were asked how many hours they sleep on a school night. To describe the typical sleep duration and address potential outliers, which measure of central tendency would be most appropriate?

Answer Choices:
Mean
Median
Mode

Answer: Median

Question: Match the variable with the type of graph that should be used for that variable. As a friendly reminder, means, medians, and modes are displayed using a line graph, histogram, or bar graph, depending on the scale of measurement (nominal, ordinal, interval, ratio) used for the independent variable you are graphing.

Answer Choices:
The best selling car brands
Average age in years
The most popular types of fruit
Average temperature in Fahrenheit
bar graph
line graph or histogram

Answer: The best selling car brands – bar graph
Average age in years – line graph or histogram
The most popular types of fruit – bar graph
Average temperature in Fahrenheit – line graph or histogram

Question: The 50th percentile score for household income in the United States is currently $41,600. What statistic of central tendency is this?

Answer Choices:
Mean
Median
Mode

Answer: Median

Question: A research report summarizes the results of a one-tail hypothesis test by stating, “z = 1.2, p > .05.” If the test was conducted with a significance level of 0.05, which of the following is a correct interpretation of this report?

Answer Choices:
The null hypothesis was rejected, and the probability of a Type I error exceeds .05.
The null hypothesis was not rejected, and the probability of a Type I error exceeds .05.
The null hypothesis was rejected, and the probability of a Type II error exceeds .05.
The null hypothesis was not rejected, and the probability of a Type I error exceeds .05.

Answer: The null hypothesis was not rejected, and the probability of a Type I error exceeds .05.

Question: Which of the following statements is NOT accurate with respect to the power of a hypothesis test?

Answer Choices:
The power of a test indicates the probability that the test will correctly reject a false null hypothesis.
Increasing the sample size will enhance the power of a hypothesis test.
Reducing the standard deviation will enhance the power of a hypothesis test.
Increasing the standard deviation will increase the power of a hypothesis test.

Answer: Increasing the standard deviation will increase the power of a hypothesis test.

Question: A researcher believes that participating in extracurricular sports during childhood is associated with heightened self-esteem in adolescence. The researcher is aware that, for the overall population of adolescents, scores on a validated self-esteem questionnaire have a mean of μ = 40 and a standard deviation of σ = 5. To test their hypothesis, the researcher gathers a sample of 25 adolescents who participated in extracurricular sports during childhood. They request these participants to complete the self-esteem questionnaire, yielding an average score of M = 42. The researcher intends to conduct a hypothesis test and wants to ensure that all the necessary assumptions are satisfied. Which of the following conditions is NOT a required assumption for the researcher’s hypothesis test?

Answer Choices:
The distribution of the mean scores for the 25 adolescents who participated in extracurricular sports during childhood must follow a normal distribution.
The 25 adolescents who participated in extracurricular sports during childhood must be randomly selected.
The standard deviation of the 25 adolescents who participated in extracurricular sports during childhood must be equal to the standard deviation of the overall population of adolescents.
The mean of the scores for the overall population of adolescents must be the same as the mean of the scores for the 25 adolescents who participated in extracurricular sports during childhood.

Answer: The standard deviation of the 25 adolescents who participated in extracurricular sports during childhood must be equal to the standard deviation of the overall population of adolescents.

Question: A workshop aimed at enhancing leadership skills is provided to a sample drawn from a population with a mean μ = 110 and a standard deviation σ = 20. Following the workshop, the sample mean is observed as M = 100. Given this information, the effect size, evaluated through Cohen’s d, can be categorized as which of the following?

Answer Choices:
large effect
no significant effect
medium effect
small effect

Answer: medium effect

Question: In evaluating the impact of a treatment, a researcher performs a t-test with a sample size of n = 16 individuals. The hypothesis test, conducted at a significance level of α = 0.05, yields a statistically significant result with t = 2.61. How should this outcome be communicated in the literature?

Answer Choices:
t(17) = 2.61, p > .05
t(16) = 2.61, p < .05
t(16) = 2.61, p > .05
t(15) = 2.61, p < .05

Answer: t(15) = 2.61, p < .05

Question: A researcher believes that participating in extracurricular sports during childhood is associated with heightened self-esteem in adolescence. The researcher is aware that, for the overall population of adolescents, scores on a validated self-esteem questionnaire have a mean of μ = 20. To test their hypothesis, the researcher plans to use an α=0.01, and gathers a sample of 25 adolescents who participated in extracurricular sports during childhood. They request these participants to complete the self-esteem questionnaire, yielding an average score of M = 21, a sum of squares ss = 216, and a standard deviation of s = 3. What is the alternative hypothesis?

Answer Choices:
H1: μ>20
H0: μ>20
H1: μ<20
H0: μ<20

Answer: H1: μ>20

Question: A researcher believes that participating in extracurricular sports during childhood is associated with heightened self-esteem in adolescence. The researcher is aware that, for the overall population of adolescents, scores on a validated self-esteem questionnaire have a mean of μ = 20. To test their hypothesis, the researcher plans to use an α=0.01, and gathers a sample of 16 adolescents who participated in extracurricular sports during childhood. They request these participants to complete the self-esteem questionnaire, yielding an average score of M = 21, a sum of squares ss = 135, and a standard deviation of s = 3. What type of hypothesis test should you conduct to determine whether adolescents who participated in extracurricular sports during childhood have higher self-esteem compared to the general population?

Answer Choices:
t-test for one sample
z-test for one sample
t-test for two related samples
t-test for two independent samples

Answer: t-test for one sample

Question: When should we conduct a hypothesis test using a t-statistic instead of a z-statistic?

Answer Choices:
When the population distribution is not normal.
When the standard deviation of the population is unknown.
When the standard deviation of the sample is unknown.
When the sample size is n = 30 or larger.

Answer: When the standard deviation of the population is unknown.

Question: A researcher believes that participating in extracurricular sports during childhood is associated with heightened self-esteem in adolescence. The researcher is aware that, for the overall population of adolescents, scores on a validated self-esteem questionnaire have a mean of μ = 20. To test their hypothesis, the researcher gathers a sample of 25 adolescents who participated in extracurricular sports during childhood. They request these participants to complete the self-esteem questionnaire, yielding an average score of M = 22, a sum of squares ss = 72, and a standard deviation of s = 3. Use the appropriate test with α = 0.01 to determine whether adolescents who participated in extracurricular sports during childhood have higher self-esteem compared to the general population. Based on the computed sample statistics, make a decision regarding whether to reject or fail to reject the null hypothesis in this situation.

Answer Choices:
We should reject the alternative hypothesis.
We should not reject the alternative hypothesis.
We should reject the null hypothesis.
We should not reject the null hypothesis.

Answer: We should reject the null hypothesis.

Question: A researcher believes that participating in extracurricular sports during childhood is associated with heightened self-esteem in adolescence. The researcher is aware that, for the overall population of adolescents, scores on a validated self-esteem questionnaire have a mean of μ = 20. To test their hypothesis, the researcher gathers a sample of 25 adolescents who participated in extracurricular sports during childhood. They request these participants to complete the self-esteem questionnaire, yielding an average score of M = 21.5 and a standard deviation of s = 3. Given this information, the effect size, evaluated through Cohen’s d, can be categorized as which of the following?

Answer Choices:
no significant effect
medium effect
small effect
large effect

Answer: small effect

Question: A researcher hypothesizes that students who study from the electronic version of the textbook achieve lower quiz scores than those who study from the printed version. To test this hypothesis, the researcher selected a sample of n = 10 students who used the electronic version of the course textbook and another sample of n = 10 students who used the printed version. Subsequently, it was found that students who used the electronic version of the course textbook had an average score of M = 85 with a SS = 160. On the other hand, students who used the printed version of the course textbook had an average score of M = 93 on the final exam with an SS = 200. Use the appropriate test with α=0.01, to determine whether students who studied from electronic screens had exam scores significantly lower to the ones that studied from printed pages. Based on the computed sample statistics, make a decision regarding whether to reject or fail to reject the null hypothesis in this situation.

Answer Choices:
We should reject the alternative hypothesis.
We should not reject the alternative hypothesis.
We should reject the null hypothesis.
We should not reject the null hypothesis.

Answer: We should reject the null hypothesis.

Question: A researcher hypothesizes that students who study from the electronic version of the textbook achieve lower quiz scores than those who study from the printed version. To test this hypothesis, the researcher selected a sample of n = 10 students who used the electronic version of the course textbook and another sample of n = 10 students who used the printed version. Subsequently, it was found that students who used the electronic version of the course textbook had an average score of M = 85 with a SS = 160. On the other hand, students who used the printed version of the course textbook had an average score of M = 93 on the final exam with an SS = 200. What is the alternative hypothesis?

Answer Choices:
H1: μ1<μ2
H0: μ1>μ2
H0: μ1<μ2
H1: μ1>μ2

Answer: H1: μ1<μ2

Question: Which of the following accurately describes the 90% confidence interval for an independent-measures study for which a hypothesis test concludes that there is a significant difference between groups with α = .10?

Answer Choices:
The confidence interval will include the value 0.
The confidence interval will not include the value 0.

Answer: The confidence interval will not include the value 0.