if the mean of the following distribution is 27,find the value of f
Answers
Step-by-step explanation:
Class frequency (f) mid point (m) mf
0-10 8 5 40
10-20 p 15 15p
20-30 12 25 300
30-40 13 35 455
40-50 10 45 450
Total 43+p 1245+15p
Formula of mean : \frac{\sum{mf}}{N}
N
∑mf
Where N is the sum of frequencies
Since we are given a mean = 27
⇒27=\frac{1245+15p}{43+p}27=
43+p
1245+15p
⇒1161+27p=1245+15p1161+27p=1245+15p
⇒27p-15p=1245-116127p−15p=1245−1161
⇒12p=8412p=84
⇒p=\frac{84}{12}p=
12
84
⇒p=7p=7
Hence the value of p is 7