Paper 4 (9164, Section A) · June 2013 · Descriptive Statistics
The table shows the number of children below the age of 15 known to have suffered from measles in 2009 in a certain village.
| Age (in years) | Number of reported cases |
|---|---|
| Under 1 | 14 |
| 1 - 2 | 33 |
| 3 - 4 | 35 |
| 5 - 9 | 39 |
| 10 - 14 | 5 |
Age is a continuous quantity, so the class boundaries are 0 to 1, 1 to 2.5, 2.5 to 4.5, 4.5 to 9.5 and 9.5 to 14.5. Calculate the mean age, in years, of the children who suffered from the disease.
Model answer
4.1
Also accepted: 4,1, 4.13, 4,13, 4.129, 4,129
Explanation
The class midpoints that go with those boundaries are 0.5, 1.75, 3.5, 7 and 12, and the total frequency is .
So the mean age is 4.1 years correct to 2 significant figures.
Derived from ZIMSEC Statistics Paper 4, June 2013, Q1