Question

write the method of step deviation? ​

Answer 1

Answer:

Taking di = mi – a, where mi = class mark of the ith class interval and di’ = d1l = m1−al, the above formula for mean becomes

A = ∑mifi∑fi

= ∑(ldi′+a)fi∑fi

= ∑(ldi′fi+afi)∑fi

= ∑ldi′fi+∑afi∑fi

= ∑afifi∑fi + ∑ldi′fi∑fi

= a∑fi∑fi + l∑di′fi∑fi

Therefore, A = a + l ∙ ∑di′fi∑fi

This is the formula for determining the mean by step-deviation method.

I hope u would understand my answer

Answer 2

Here we will learn the step-deviation method for finding the mean of classified data.

We know that the direct method of finding the mean of classified data gives

Mean A = ∑mifi∑fi∑mifi∑fi

where m1, m2, m3, m4, mn are the class marks of the class intervals and f1, f2, f3, f4, fn  are the frequencies of the corresponding classes.