Question

If the mean of the following data is 18.75. Find the value of p.

xi	10	15	P	25	30
fi	5	10	7	8	2

Answer 1

xi	fi	fx
10	5	50
15	10	150
P	7	7P
25	8	200
30	2	60
	N = 32	`sum`fx = 7P + 460

Given

Mean = 18.75

`rArr(sumfx)/N=18.75`

`rArr(7P + 460)/32=18.75`

⇒ 7P + 460 = 18.75(32)

⇒ 7P + 460 = 600

⇒ 7P = 600 − 460

⇒ 7P = 140

`rArrP=140/7`

⇒ P = 20