The mean of the following frequency distribution is 8. Find the value of p.
x | 3 | 5 | 7 | 9 | 11 | 13 |
y | 6 | 8 | 15 | p | 8 | 4 |
First draw the table as shown below;
x | f | f × x |
3 | 6 | 18 |
5 | 8 | 40 |
7 | 15 | 105 |
9 | P | 9p |
11 | 8 | 88 |
13 | 4 | 52 |
∑f = 41 + p | ∑fx = 303 + 9p |
Given mean = 8
8 =
⇒ 8(41 + p) = 303 + 9p
⇒ 328 + 8p = 30 + 9p
⇒ 9p – 8p = 328 – 303
⇒ p = 25
So, the value of p = 25