What is the probability that the code number for a new customer will begin with a 7
1 answer:
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Answer:
Margin of error for 90% C.I: 0.065
Margin of error for 99% C.I: 0.091
Margin of error for 95% C.I: 0.077
Step-by-step explanation:
In this question, for each student, there are only two possible outcomes. Either they use a pencil to take notes, or they do not. Students are independent of each other. So we use the binomial probability distribution to solve this question.
Binomial confidence interval:
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:
For this problem, we have that:
120 students, so
90 responded favorably, so
Margin of error for 90% CI:
Here , z is the value of Z that has a pvalue of
, so
.
The margin of error is:
Margin of error for 99% CI:
Here , z is the value of Z that has a pvalue of
, so
.
The margin of error is:
Margin of error for 95% CI:
Here , z is the value of Z that has a pvalue of
, so
.
The margin of error is: