Answer:
Step-by-step explanation:
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1. A 25% discount on a skateboard is $24.75. What is the cost before the discount?
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Answer:
The 96% confidence interval estimate for the mean daily number of minutes that BYU students spend on their phones in fall 2019 is between 306.65 minutes and 317.35 minutes.
Step-by-step explanation:
Confidence interval normal
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
That is z with a pvalue of , so Z = 2.054.
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 312 - 5.35 = 306.65 minutes
The upper end of the interval is the sample mean added to M. So it is 312 + 5.35 = 317.35 minutes
The 96% confidence interval estimate for the mean daily number of minutes that BYU students spend on their phones in fall 2019 is between 306.65 minutes and 317.35 minutes.