Data and Analytics Statistical Analysis 1 — Questions and Answers
Question 1: What does the p-value represent in hypothesis testing?
- The probability the null hypothesis is true
- The probability of observing results as extreme as the data if the null hypothesis is true (Correct answer)
- The effect size of the tested variable
- The confidence interval width
Correct answer: The probability of observing results as extreme as the data if the null hypothesis is true
The p-value is the probability of obtaining results at least as extreme as observed, assuming the null hypothesis is true.
Question 2: What is the mean of the dataset: 4, 8, 6, 10, 12?
- 7
- 8 (Correct answer)
- 9
- 10
Correct answer: 8
The mean is calculated as (4+8+6+10+12)/5 = 40/5 = 8.
Question 3: What does standard deviation measure?
- The middle value in a dataset
- The most frequent value in a dataset
- The average distance of data points from the mean (Correct answer)
- The range between minimum and maximum values
Correct answer: The average distance of data points from the mean
Standard deviation quantifies the dispersion of data points around the mean, measuring how spread out values are.
Question 4: What type of correlation does a Pearson coefficient of -0.85 indicate?
- Strong positive correlation
- Weak positive correlation
- Strong negative correlation (Correct answer)
- No correlation
Correct answer: Strong negative correlation
A Pearson coefficient of -0.85 indicates a strong negative linear relationship where one variable increases as the other decreases.
Question 5: What is a Type I error in hypothesis testing?
- Failing to reject a false null hypothesis
- Rejecting a true null hypothesis (Correct answer)
- Accepting an incorrect alternative hypothesis
- Using the wrong statistical test
Correct answer: Rejecting a true null hypothesis
A Type I error (false positive) occurs when a true null hypothesis is incorrectly rejected.
Question 6: Which measure of central tendency is most resistant to outliers?
- Mean
- Median (Correct answer)
- Mode
- Range
Correct answer: Median
The median is the middle value when data is sorted, making it unaffected by extreme outlier values unlike the mean.
Data and Analytics Statistical Analysis 1
What does the p-value represent in hypothesis testing?