BAPSY Methodical & Stats Analysis 2 — Questions and Answers
Question 1: A researcher finds r = 0.85 between study hours and exam scores. What does this indicate?
- A strong positive linear relationship (Correct answer)
- Study hours cause better exam scores
- 85% of variance is explained
- The relationship is non-linear
Correct answer: A strong positive linear relationship
r = 0.85 indicates a strong positive linear relationship, but correlation does not imply causation.
Question 2: Which of the following best describes a Type II error?
- Rejecting a true null hypothesis
- Failing to reject a false null hypothesis (Correct answer)
- Setting alpha too low
- Using an underpowered test statistic
Correct answer: Failing to reject a false null hypothesis
A Type II error (beta error) occurs when a researcher fails to reject a null hypothesis that is actually false.
Question 3: In an ANOVA, the F-ratio is computed as:
- Within-group variance / Between-group variance
- Between-group variance / Within-group variance (Correct answer)
- Total variance / Error variance
- Mean square error / Mean square regression
Correct answer: Between-group variance / Within-group variance
The F-ratio in ANOVA equals between-group variance (MSB) divided by within-group variance (MSW).
Question 4: Which sampling method gives every member of a population an equal chance of being selected?
- Stratified sampling
- Cluster sampling
- Simple random sampling (Correct answer)
- Purposive sampling
Correct answer: Simple random sampling
Simple random sampling assigns each population member an equal and independent probability of selection.
Question 5: A chi-square test of independence is most appropriate when:
- Both variables are continuous
- Both variables are categorical (Correct answer)
- One variable is categorical and one is continuous
- The data are normally distributed
Correct answer: Both variables are categorical
Chi-square tests of independence evaluate whether two categorical variables are associated.
Question 6: What does statistical power refer to?
- The probability of making a Type I error
- The probability of correctly rejecting a false null hypothesis (Correct answer)
- The sample size needed for significance
- The effect size of an intervention
Correct answer: The probability of correctly rejecting a false null hypothesis
Statistical power is the probability (1 − β) of detecting a true effect when one exists.
Question 7: Which measure of central tendency is most resistant to extreme outliers?
- Mean
- Mode
- Median (Correct answer)
- Range
Correct answer: Median
The median is resistant to outliers because it is based on rank position, not actual values.
BAPSY Methodical & Stats Analysis 2
A researcher finds r = 0.85 between study hours and exam scores.
What does this indicate?