a pair of inline skates are on sale for $90. If this price represents 9% discount from the original price, what is the original
2 answers:
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Answer:
The 90% confidence interval is (0.1897, 0.2285).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence interval
, we have the following confidence interval of proportions.
In which
Z is the zscore that has a pvalue of
For this problem, we have that:
From a July 2019 survey of 1186 randomly selected Americans ages 18-29, it was discovered that 248 of them vaped (used an e-cigarette) in the past week. This means that
Construct a 90% confidence interval to estimate the population proportion of Americans age 18-29 who vaped in the past week.
So , z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:
The upper limit of this interval is:
The 90% confidence interval is (0.1897, 0.2285).