Marks | 1 | 2 | 3 | 4 | 5 |
Frequency | 2y – 2 | y – 1 | 3y – 4 | 3 – y | 6 – 2y |
The table above is the distribution of data with mean equals to 3. Find the value of y.
-
A.
5 -
B.
2 -
C.
3 -
D.
6
Correct Answer: Option B
Explanation
Marks (x) | 1 | 2 | 3 | 4 | 5 | |
Frequency (f) | 2y – 2 | y – 1 | 3y – 4 | 3 – y | 6 – 2y | 3y + 2 |
fx | 2y – 2 | 2y – 2 | 9y – 12 | 12 – 4y | 30 – 10y | 26 – y |
Mean = (frac{sum fx}{sum f})
(3 = frac{26 – y}{3y + 2})
(3(3y + 2) = 26 – y)
(9y + 6 = 26 – y)
(9y + y = 26 – 6)
(10y = 20 implies y = 2)
There is an explanation video available below.