Part A
Multiply each age with its corresponding frequency
- 19*2 = 38
- 20*3 = 60
- 21*1 = 21
- 22*4 = 88
- 23*1 = 23
Then add up those products
38+60+21+88+23 = 230
We divide that sum over the total frequency of 11 (since 2+3+1+4+1 = 11).
mean = 230/11 = 20.9 approximately
Answer: 20.9
Nice work on getting the correct answer.
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Part B
x = age of the new player
Adding x to the sum of the products 230, and then dividing over 11+1 = 12 will get us the new mean of 22.
The 230 represents the sum of the ages of the original eleven people. The expression 230+x represents the sum of the twelve ages.
So,
(230+x)/12 = 22
230+x = 12*22
230+x = 264
x = 264-230
x = 34
Answer: 34