On the first math test, Keiko answered 19 out of 25 questions correctly. On the second test she got 17 out of 20 correct. On whi
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Answer: 2285
Step-by-step explanation:
Formula to find the sample size is given by :-
, where p = prior estimate of population proportion.
E= Margin of error.
= z-value for confidence interval of c.
Given : Confidence interval : 95%
From the z-value table , the z-value for 95% confidence interval =
The General Social Survey reported a sample where about 61% of US residents thought marijuana should be made legal.
i.e. the prior estimate of population proportion of US residents thought marijuana should be made legal : p=0.61
[∵ sample proportion is the best estimate for population proportion.]
Margin of error : E= 2%=0.02
Now, the required minimum sample size would be :-
Simplify ,
Thus , we need to survey <u>2285</u> Americans .