Allison goes to the store with $100. She buys the same gift for 7 of her friends. She has $16 dollars left. How much did each gi
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Answer: 208.
Step-by-step explanation:
The formula to find the minimum sample size is given by :-
(1)
, where z* = critical z-value (two tailed).
= Standard deviation ( from prior study ) and E = Margin of error.
As per given , we have
Margin of error : E= 0.29
Confidence level = 85%
Significance level =
Using z-table , the critical value (two -tailed)=
As per previous study , Variance =
Now, the required minimum sample size = [Substitute the values in formula (1)]
[ Round to the next integer]
Hence, the minimum number of third graders that must be included in a sample = 208.