Answer:
We need to select at least 1068 sales transactions.
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:
95% confidence level
So , z is the value of Z that has a pvalue of , so .
How many randomly selected sales transactions must be surveyed to determine the percentage that transpired over the Internet?
We need to survey at least n sales transactions.
Within three percentage points, so M = 0.03.
We do not know the population proportion, so we estimate it at , which is when we are going to need the largest sample size.
Rounding up
1068
We need to select at least 1068 sales transactions.