DAC DAC Statistical Methods & Analytics 1 — Questions and Answers
Question 1: What does the term 'mean' refer to in descriptive statistics?
- The most frequently occurring value
- The middle value when data is sorted
- The arithmetic average of all values (Correct answer)
- The difference between the highest and lowest values
Correct answer: The arithmetic average of all values
The mean is calculated by summing all data values and dividing by the count of values, giving the arithmetic average.
Question 2: Which measure of central tendency is most resistant to the influence of extreme outliers?
- Mean
- Variance
- Median (Correct answer)
- Standard deviation
Correct answer: Median
The median, being the middle value of a sorted dataset, is not affected by extreme outliers the way the mean is.
Question 3: In hypothesis testing, what does a p-value less than 0.05 typically indicate?
- The null hypothesis is definitely true
- There is statistically significant evidence to reject the null hypothesis (Correct answer)
- The sample size is too small
- The data is normally distributed
Correct answer: There is statistically significant evidence to reject the null hypothesis
A p-value below the significance threshold (commonly 0.05) indicates the observed results are unlikely under the null hypothesis, supporting its rejection.
Question 4: What does standard deviation measure in a dataset?
- The most common value in the data
- The average distance of data points from the mean (Correct answer)
- The total range of values
- The correlation between two variables
Correct answer: The average distance of data points from the mean
Standard deviation quantifies how spread out the data values are around the mean — a larger value indicates more variability.
Question 5: Which type of correlation coefficient is used to measure the linear relationship between two continuous variables?
- Spearman's rho
- Chi-square
- Pearson's r (Correct answer)
- Cramer's V
Correct answer: Pearson's r
Pearson's r measures the strength and direction of the linear relationship between two continuous, normally distributed variables.
Question 6: What is the purpose of a confidence interval in statistical analysis?
- To determine the exact population parameter
- To provide a range of values likely to contain the true population parameter (Correct answer)
- To test whether two groups are significantly different
- To measure the spread of a single variable
Correct answer: To provide a range of values likely to contain the true population parameter
A confidence interval gives a range of plausible values for a population parameter, with a specified level of confidence (e.g., 95%).
DAC DAC Statistical Methods & Analytics 1
What does the term 'mean' refer to in descriptive statistics?