Q) Using step-deviation method, find mean for the following frequency distribution:

ICSE Specimen Question Paper (SQP)2025

Ans:

Step 1: Let’s re-organize the data in the table:

Step 2: Here we have = 30,  = – 12, a = 52.5, h = 15

Given that the total of frequencies = 40

∴  Mean = a + x h

= 52.5 + x 15

= 52.5 – 6

= 46.5

Therefore, the mean value is 46.5

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