Question

Find the missing information from the following
Particulars Group I Group II Group III Combined
Number
Standard Deviation
Mean
50
6
113
?
7
?
90
?
115
200
7.746
116

Answer 1

This is easy first step is to calculate X which is equal to sum of clasd intetval(eg10-20)and divide it by 2 next step is to calculate D which is equal to X-A (is the middle term of X) amd then calculate U=D/C(C is the gap between the class intervals) after this multiply frequencies with their respective U and add all of them (EFU)amd then add all frequencies (EF) and apply the formula: mean =A+(C*EFU /EF)