Answer:
The minimum sample size is n = 75 so that the desired margin of error is 5 or less.
Step-by-step explanation:
We are given the following in the question:
Population variance = 484
Standard deviation =

Confidence level = 0.95
Significance level = 0.05
Margin of error = 5
Formula:
Margin of error =


Putting values, we get

Thus, the minimum sample size is n = 75 so that the desired margin of error is 5 or less.
Answer:
you simplify it? I dont really know. :/
Step-by-step explanation:
Answer: 15 boys
Explanation: ratio 5:7
5 + 7 = 12
Number of boys = 5/12 × 36