Question

Mean of grouped data calculated using direct method. Assumed mean method or step deviation varies slightly

Answer 1

this question is asked in IB security assistant exam, your question is incomplete. A complete question is ----> Mean of a grouped data calculated

using direct method, assumed mean

method or step deviation method:

(a) is the same.

(b) varies slightly

(c) has huge variation

(d) none of these.

answer is option (a) is the same.

explanation : mean of grouped data can be calculated by three different methods.

e.g., by direct method , using formula : $\frac{\Sigma{f_ix_i}}{\Sigma{f_i}}$

by assumed mean method , using formula : $a+\frac{\Sigma{f_id_i}}{\Sigma{f_i}}$

and by step deviation method , using formula : $a+h\frac{\Sigma{f_iu_i}}{\Sigma{f_i}}$

of course, all the given methods have different formula with different terms but result obtained by all the three methods is the same.

Answer 2

Thank you for asking this question. Here is your answer:

The options for this question are missing. Here are the missing options:  (A) Is the same (B) Varies slightly (C) has huge variation (D) none of these

The direct method is: Sum of all observation/ total number of observation

Assumed mean method

a = Assumed mean

= a + sum(FX)/sumX

And the other one is deviation method which takes the less time to solve it

So A is the final answer for this question.