Question 1

Which of the following best describes the purpose of frequency statistics in psychological research?

Accepted Answer

To describe how often different scores or values occur in a dataset.

Question 2

A researcher collects GRE scores ranging from 130 to 170. What type of graph would best display the frequency of each score?

Accepted Answer

Histogram

Question 3

Given the following dataset: 130, 135, 140, 143, 145, 150, 153, 155, 160, 161, which statement best describes its distribution?

Accepted Answer

It is a normal distribution.

Question 4

Which measure of central tendency is most appropriate for a dataset with extreme outliers, such as household incomes including Jeff Bezos' $78 billion?

Accepted Answer

Median

Question 5

If a dataset has low variability, what does this indicate about the scores?

Accepted Answer

Scores are similar and clustered together.

Question 6

Calculate the mean for the following scores: 10, 20, 30, 40, 50. Use the formula $$	ext{Mean} = \frac{\sum x}{N}.$$

Accepted Answer

$$	ext{Mean} = 30$$

Question 7

A sample of test scores has a mean of 100 and a standard deviation (SD) of 15. What percentage of scores are expected to fall within one SD of the mean in a normal distribution?

Accepted Answer

68%

Question 8

Which of the following best explains why the median is often preferred over the mean in skewed distributions?

Accepted Answer

The median is less affected by extreme values.

Question 9

In hypothesis testing, what does a p-value represent?

Accepted Answer

The probability that results occurred by chance.

Question 10

A researcher finds a p-value of 0.03 when comparing two groups. What does this indicate?

Accepted Answer

There is less than a 5% chance the results are due to random variation.

Question 11

Which factor can increase the likelihood of finding a statistically significant result even if the effect is trivial?

Accepted Answer

Large sample size

Question 12

Why is it important to report both p-values and effect sizes in psychological research?

Accepted Answer

P-values show if results are unlikely due to chance, effect sizes show how meaningful the differences are.

Question 13

A university study finds that students who text during class have a mean loneliness score of 78, while those who do not text have a mean score of 81. What additional information is needed to determine if this difference is meaningful?

Accepted Answer

The standard deviation of each group

Question 14

Which of the following is a limitation of statistical significance testing?

Accepted Answer

Statistically significant results can still be due to chance or trivial differences.

Question 15

If a dataset is positively skewed, which of the following is true?

Accepted Answer

The tail is on the right side of the distribution.

Question 16

Which formula correctly calculates the standard deviation (SD) for a sample?

Accepted Answer

$$SD = \sqrt{\frac{\sum (x_i - \bar{x})^2$}{N-1}}$$

Question 17

Which scenario best illustrates the concept of 'signal' versus 'noise' in hypothesis testing?

Accepted Answer

Comparing the mean scores of two groups with similar standard deviations.

Question 18

Jacob Cohen proposed 'effect size' as a complement to p-values. What does effect size measure?

Accepted Answer

The magnitude of the difference between groups.

Question 19

A researcher tests 100 hypotheses in a single study. What is a potential risk associated with this approach?

Accepted Answer

Increased chance of false positives.

Question 20

Which of the following statements is true regarding normal distributions?

Accepted Answer

The mean, median, and mode are all equal.

Descriptive and Inferential Statistics in Psychology

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