Mia's Cafe has regular coffee and decaffeinated coffee. This morning, the cafe served 25 coffees in all, 15 of which were regula
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Answer:
The statement that "the margin of error was given as percentage points" means that the population proportion is estimated to be with a certain level of confidence, within the interval
; where
is likely to contain the true population percentage of people that prefer chocolate pie.
Step-by-step explanation:
The margin of error for proportions is given by the following formula:
Where:
is the critical value that corresponds to the confidence level; the confidence level being
,
is the sample's proportion of successes,
is the size of the sample.
In this exercise we have that and that the margin of error is 0.05.
Therefore if we replace in the formula to calculate the confidence interval we get:
Which means that the true population proportion is estimated to be, with a certain confidence level, within the interval (0.09, 0.19).