UExcel Statistics 1 — Questions and Answers
Question 1: What does the standard deviation measure in a dataset?
- The average of all values
- The spread or dispersion of values around the mean (Correct answer)
- The middle value in a sorted dataset
- The difference between the highest and lowest values
Correct answer: The spread or dispersion of values around the mean
Standard deviation measures how spread out values are around the mean.
Question 2: Which of the following is a characteristic of a normal distribution?
- It is skewed to the right
- The mean, median, and mode are all equal (Correct answer)
- It has two peaks
- The tails touch the x-axis
Correct answer: The mean, median, and mode are all equal
In a normal distribution, the mean, median, and mode are all equal and located at the center.
Question 3: A p-value of 0.03 in hypothesis testing means:
- There is a 3% chance the null hypothesis is true
- There is a 3% probability of obtaining the observed result if the null hypothesis is true (Correct answer)
- The effect size is small
- The result is not statistically significant
Correct answer: There is a 3% probability of obtaining the observed result if the null hypothesis is true
A p-value represents the probability of observing the data if the null hypothesis were true.
Question 4: What is the median of the dataset: 3, 7, 9, 12, 15?
- 7
- 9 (Correct answer)
- 10
- 12
Correct answer: 9
The median is the middle value of a sorted dataset, which is 9 in this case.
Question 5: Which sampling method gives every member of the population an equal chance of being selected?
- Convenience sampling
- Stratified sampling
- Simple random sampling (Correct answer)
- Cluster sampling
Correct answer: Simple random sampling
Simple random sampling ensures each population member has an equal probability of selection.
Question 6: A correlation coefficient of -0.85 indicates:
- A weak positive relationship
- No relationship
- A strong negative relationship (Correct answer)
- A weak negative relationship
Correct answer: A strong negative relationship
A correlation coefficient of -0.85 indicates a strong negative linear relationship between two variables.
UExcel Statistics 1
What does the standard deviation measure in a dataset?