Question: Find the weighted average.
value f
8 8
7 12
6 10
5 4
4 3
3 0
2 0
1 1
My work:
ybar= (8x8)+ (7x12) + (6x10) + (5x4)+ (4x3) + (3x0) + (2x0)+ (1x0)/ 8 (but i'm not sure).
Apparently, the answer is 6.34 (according to the practice quiz but I'm not sure what I'm doing wrong).
So I got 240 and divided that by the number of values and got 30 but that is nowhere near the right answer. I also know that since the average is weighted it is not 8+12+10+4+3+0+0+1/8.
The weighted sum is (8x8)+ (7x12) + (6x10) + (5x4)+ (4x3) + (3x0) + (2x0)+ (1x1) = 241
The number of values is 8+12+10+4+3+0+0+1 = 38
Try your division now.
To find the weighted average, you need to multiply each value by its corresponding weight, then sum up these products, and finally divide by the sum of the weights.
In your case, the values are: 8, 7, 6, 5, 4, 3, 2, 1.
And the weights are: 8, 12, 10, 4, 3, 0, 0, 1.
Let's calculate the weighted average using your formula.
ybar = (8 x 8) + (7 x 12) + (6 x 10) + (5 x 4) + (4 x 3) + (3 x 0) + (2 x 0) + (1 x 1) / (8)
ybar = (64) + (84) + (60) + (20) + (12) + (0) + (0) + (1) / 8
ybar = 241 / 8
ybar ≈ 30.125
Your calculation seems to be incorrect. The correct value is approximately 30.125, not 6.34. Please double-check your calculations and make sure you are multiplying the values by their corresponding weights correctly and dividing by the sum of the weights.