Answer: 868 miles
Step-by-step explanation:
Given: The scale from a map to actual distance is 2.5 cm to 620 miles.
i.e. 1 cm on map =
If the distance on the map between Chicago and Boston is about 3.5 cm.
Then, the actual distance between them =
Hence, the approximate distance between Chicago and Boston = 868 miles.
Answer:
We need a sample size of at least 383.
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:
85% confidence level
So , z is the value of Z that has a pvalue of
, so
.
How large a sample would be required in order to estimate the fraction of tenth graders reading at or below the eighth grade level at the 85% confidence level with an error of at most 0.03
We need a sample size of at least n.
n is found with
Then
Rounding up
We need a sample size of at least 383.