The table shows the age distribution in years of a group of people Age(in years) 1 - 5 6 - 10 11 - 15 16 - 20 21 - 25 26 - 30 Number of people 18 12 25 15 2...
Question 1 Report
The table shows the age distribution in years of a group of people
| Age(in years) | 1 - 5 | 6 - 10 | 11 - 15 | 16 - 20 | 21 - 25 | 26 - 30 |
| Number of people | 18 | 12 | 25 | 15 | 20 | 10 |
Using an assume mean of 13 years, find the mean age of the people.
Answer Details
Method. Assumed mean \(A = 13\), class width \(c = 5\), \(u = \dfrac{x - 13}{5}\) where \(x\) is the class midpoint.
| Age (years) | Midpoint \(x\) | \(u\) | \(f\) | \(fu\) |
|---|---|---|---|---|
| 1 - 5 | 3 | -2 | 18 | -36 |
| 6 - 10 | 8 | -1 | 12 | -12 |
| 11 - 15 | 13 | 0 | 25 | 0 |
| 16 - 20 | 18 | 1 | 15 | 15 |
| 21 - 25 | 23 | 2 | 20 | 40 |
| 26 - 30 | 28 | 3 | 10 | 30 |
| Total | 100 | 37 |
Mean age.
\[ \bar{x} = A + \left(\frac{\sum fu}{\sum f}\right)c = 13 + \frac{37}{100}\times 5 = 13 + 1.85 = \mathbf{14.85 \text{ years}} \]Download The App On Google Playstore
Everything you need to excel in your exams
Personalized AI Learning Chat Assistant
200,000+ Exam Questions Across IGCSE, JAMB, WAEC & NECO
Over 3,900 Lesson Notes
Offline Support - Learn Anytime, Anywhere
Green Bridge Timetable
Literature Summaries & Potential Questions
Track Your Performance & Progress
In-depth Explanations for Comprehensive Learning