Question

Please solve this question ​

Answer 1

Given:

Number of mice and frequency

Mean = 7

To find:

The value of x.

Solution:

Number of mice = X

Frequency = Y

XY = Multiply X and Y values.

X Y XY

5 4 20

6 13 78

7 16 112

8 x 8x

9 6 54

Sum of Y = 4 + 13 + 16 + x + 6

= 39 + x

Sum of XY = 20 + 78 + 112 + 8x + 54

= 8x + 264

Mean formula:

`$Mean = (\Sigma XY )/(\Sigma Y)`

`$7=(8x+264)/(39+x)`

Do cross multiplication.

`7(39+x)=(8x+264)`

`273+7x=8x+264`

Subtract 264 from both sides, we get

`9+7x=8x`

Subtract 7x from both sides, we get

`9=x`

The value of x is 9.