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Calculate the standard deviation using step deviation method.

class Frequency

0-10 2

10-20 4

20-30 6

30-40 8

40-50 6

50-60 4

60-70 2

**Answer is 15.81**

but it is applying only for first three methods but it is 1.581 in standard deviation method

please clarify

but it is applying only for first three methods but it is 1.581 in standard deviation method

$S\mathrm{tan}darddeviation=\sqrt{\frac{{\sum}_{}f{d}_{x}^{I}}{N}-{\left(\frac{{\sum}_{}f{d}_{x}^{I}}{N}\right)}^{2}}\times h$

Where

**h**refers to the class size which is

**10**in the given question.I thing you forgot to treat

**h**while solving the question yourself. So you just have to multiply your current answer by 10.

**If this is not the case and your answer is different for some other reason using step deviation method, do get back to us.**

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