Question

Find the missing value of p for the following distribution whose mean is 12.58.

x:	5	8	10	12	p	20	25
f:	2	5	8	22	7	4	2

Answer 1

\(Mean =\frac{ \sum fx}{N}\)

= \(\frac{(7p\, +\, 524)}{50}\)

Mean = 12.58

So, \(\frac{(7p\, +\, 524)}{50}\) = 12.58 

7p + 524 = 12.58 x 50 

7p + 524 = 629 

7p = 629 – 524 = 105 

p = \(\frac{105}{7}\) 

= 15 

⇒ The value of p is 15.