# Find the mean: Class interval: (10 – 30, 30 – 50, 50 – 70, 70 – 90, 90 – 110, 110 – 130) Frequency: (5, 8, 12, 20, 3, 2)

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Find the mean:

 Class interval: 10-30 30-50 50-70 70-90 90-110 110-130 Frequency: 5 8 12 20 3 2

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Let’s consider the assumed mean (A) = 60

From the table it’s seen that,

A = 60 and h = 20

Mean = A + h x ($\frac{Σf_i u_i}{N}$)

= 60 + 20 x ($\frac{14}{50}$)

= 60 + $\frac{28}{5}$

= 60 + 5.6

= 65.6