CBDA Statistical Analysis & Methods 1 — Questions and Answers
Question 1: In hypothesis testing, what does a p-value of 0.03 indicate when using a significance level of 0.05?
- Fail to reject the null hypothesis
- Reject the null hypothesis; the result is statistically significant (Correct answer)
- The effect size is practically significant
- The sample size was too small
Correct answer: Reject the null hypothesis; the result is statistically significant
A p-value of 0.03 is less than α = 0.05, so you reject the null hypothesis, meaning the result is statistically significant.
Question 2: Which measure of central tendency is MOST resistant to extreme outliers in a business dataset?
- Mean
- Median (Correct answer)
- Mode
- Range
Correct answer: Median
The median is the middle value and is not affected by extreme values, making it robust to outliers.
Question 3: A CBDA analyst runs a chi-square test. What type of data relationship is this test designed to evaluate?
- Linear relationship between two continuous variables
- Association between two categorical variables (Correct answer)
- Difference in means between two groups
- Correlation between a continuous and a binary variable
Correct answer: Association between two categorical variables
The chi-square test of independence evaluates whether two categorical variables are statistically associated.
Question 4: Standard deviation measures which characteristic of a dataset?
- The average value of the dataset
- The spread or dispersion of values around the mean (Correct answer)
- The most frequently occurring value
- The difference between the maximum and minimum values
Correct answer: The spread or dispersion of values around the mean
Standard deviation quantifies how much individual data points deviate from the mean on average.
Question 5: In a simple linear regression model, the R-squared value represents:
- The slope of the regression line
- The proportion of variance in the dependent variable explained by the independent variable (Correct answer)
- The statistical significance of the model
- The number of outliers in the dataset
Correct answer: The proportion of variance in the dependent variable explained by the independent variable
R-squared (coefficient of determination) indicates how much of the variability in Y is explained by X, ranging from 0 to 1.
Question 6: What is a Type I error in the context of business hypothesis testing?
- Failing to detect a real effect that exists
- Concluding an effect exists when it does not (false positive) (Correct answer)
- Using the wrong statistical test for the data type
- Having an insufficient sample size
Correct answer: Concluding an effect exists when it does not (false positive)
A Type I error (false positive) occurs when you reject a true null hypothesis, concluding an effect exists when it does not.
CBDA Statistical Analysis & Methods 1
In hypothesis testing, what does a p-value of 0.03 indicate when using a significance level of 0.05?