IAI Actuarial Core Principles · Actuarial Statistics · Exploratory data analysis
A sample of 8 monthly claim counts for a small Pune motor portfolio is: 4, 7, 7, 9, 10, 12, 15, 20. What is the sample mean and the median respectively?
The mean is 10.5 because the total of 84 is divided by 8 observations. The median is 9.5 because with an even sample size it is the average of the 4th and 5th ordered values, 9 and 10.
- A10.5 and 9.5Correct
- B10.5 and 10
- C9.5 and 9.5
- D10.5 and 9
- 9.5 and 10
Explanation
Sum = 4+7+7+9+10+12+15+20 = 84, so mean = 84/8 = 10.5. With 8 observations the median is the average of the 4th and 5th ordered values: (9+10)/2 = 9.5. Option 10.5 and 10 wrongly takes the 5th value as the median.
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