At a carnival, a particular game requires the player to spin a wheel. When a child plays, the game operator allows them to conti
1 answer:
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Answer:
C. 50
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error is:
The higher the margin of error, the wider an interval is.
As the sample size increases, the margin of error decreases. If we want a widest possible interval, we should select the smallest possible confidence interval.
So the correct answer is:
C. 50
Answer:
test statistic (Z) is 2.5767 and p-value of the test is .009975
Step-by-step explanation:
: percentage of students who smoke did not change
: percentage of students who smoke has changed
z-statistic for the sample proportion can be calculated as follows:
z= where
- p(s) is the sample proportion of smoking students (
=0.25)
- p is the proportion of smoking students in the survey conducted five years ago (18% or 0.18)
- N is the sample size (200)
Then, z= ≈ 2.5767
What is being surveyed is if the percentage of students who smoke has changed over the last five years, therefore we need to seek two tailed p-value, which is .009975.
This p value is significant at 99% confidence level. Since .009975 <α/2=0.005, there is significant evidence that the percentage of students who smoke has changed over the last five years