Free IMSA Statistical Analysis Questions and Answers — Questions and Answers
Question 1: What is the mean of the following set of numbers: 4, 8, 15, 16, 23, 42?
- 19 (Correct answer)
- 18
- 20
- 21
Correct answer: 19
The mean is calculated by adding all the numbers and dividing by the count: (4 + 8 + 15 + 16 + 23 + 42) / 6 = 19.
Question 2: What is the median of the following set of numbers: 7, 3, 9, 12, 15?
- 9 (Correct answer)
- 7
- 12
- 15
Correct answer: 9
The median is the middle number when the data set is ordered: 3, 7, 9, 12, 15. The middle number is 9.
Question 3: Which of the following measures of central tendency is most affected by outliers?
- Median
- Mean (Correct answer)
- Mode
- Range
Correct answer: Mean
The mean is most affected by outliers because it takes into account all values, while the median and mode are less affected.
Question 4: What is the mode of the following set of numbers: 2, 4, 4, 4, 6, 7, 8, 9?
- 4 (Correct answer)
- 2
- 6
- 7
Correct answer: 4
The mode is the number that appears most frequently in the data set, which is 4 in this case.
Question 5: Which of the following is a measure of variability?
- Median
- Standard Deviation (Correct answer)
- Mean
- Mode
Correct answer: Standard Deviation
Standard deviation is a measure of the amount of variation or dispersion in a set of values.
Question 6: If a dataset has a mean of 50 and a standard deviation of 5, what is the z-score of a data point that is 60?
- 2 (Correct answer)
- 1
- 3
- 4
Correct answer: 2
The z-score is calculated as (X - mean) / standard deviation. (60 - 50) / 5 = 2.
Question 7: In a normal distribution, what percentage of data falls within one standard deviation of the mean?
- 68% (Correct answer)
- 50%
- 95%
- 99%
Correct answer: 68%
Approximately 68% of the data falls within one standard deviation of the mean in a normal distribution.
Question 8: What is the interquartile range (IQR) of the following dataset: 1, 3, 7, 9, 12, 15, 18, 20?
- 8 (Correct answer)
- 6
- 7
- 9
Correct answer: 8
IQR is the difference between the 75th percentile (Q3) and the 25th percentile (Q1). Here, Q1 is 6 and Q3 is 14. So, IQR = 14 - 6 = 8.
Question 9: What type of correlation exists if an increase in one variable corresponds to an increase in another variable?
- Positive correlation (Correct answer)
- Negative correlation
- No correlation
- Zero correlation
Correct answer: Positive correlation
A positive correlation means that as one variable increases, the other variable also increases.
Question 10: Which graphical representation is best used to show the distribution of a data set?
- Histogram (Correct answer)
- Bar Chart
- Pie Chart
- Line Graph
Correct answer: Histogram
A histogram is used to show the distribution of a data set by grouping data points into ranges.
Question 11: What does a p-value less than 0.05 indicate in a hypothesis test?
- The null hypothesis is rejected (Correct answer)
- The null hypothesis is accepted
- The results are not statistically significant
- The data follows a normal distribution
Correct answer: The null hypothesis is rejected
A p-value less than 0.05 indicates that there is strong evidence against the null hypothesis, so it is rejected.
Free IMSA Statistical Analysis Questions and Answers
What is the mean of the following set of numbers: 4, 8, 15, 16, 23, 42?