WBBSEClass XMathematicsStatistics04 Mark2025 Easy

QQuestion

The age of 100 persons present in a workshop is given in the following table. Find the average age of 100 people (by any method):

Age Group Number of People
10 – 20 8
20 – 30 12
30 – 40 20
40 – 50 22
50 – 60 18
60 – 70 20

Exam-ready answer 04 Mark

Answer

Age Group Number of People (f) Midpoint (x) fx
10 – 20 8 15 120
20 – 30 12 25 300
30 – 40 20 35 700
40 – 50 22 45 990
50 – 60 18 55 990
60 – 70 20 65 1300


Σ fx = 120 + 300 + 700 + 990 + 990 + 1300

= 4400

Total number of people:

Σ f = 8 + 12 + 20 + 22 + 18 + 20

= 100

\bar{x} = \frac{4400}{100}

\bar{x} = 44

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