A university found that 20% of its students withdraw without completing the introductory statistics course. Assume that 20 stude
1 answer:
Answer:
Step-by-step explanation:
Given that a university found that 20% of its students withdraw without completing the introductory statistics course.
Each student is independent of the other and there are only two outcomes
X no of students in the registered 20 is binomial with p = 0.2
a)the probability that two or fewer will withdraw.
=
b. Compute the probability that exactly four will withdraw.
=
c. Compute the probability that more than three will withdraw.
d. Compute the expected number of withdrawals.
E(x) = np = 4
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5 = (8 x K) / (8 + K)
40 + 5 K = 8K
40 = 3K
King can do the job in 13.33 Hours
King could mow (1 / 13.33) of the lawn in one hour.
5 = (8 x K) / (8 + K)
40 + 5 K = 8K
40 = 3K
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Answer:
a) 272 used at least one prescription medication.
b) The 90% confidence interval estimate of the percentage of adults aged 57 through 85 years who use at least one prescription medication is (85.6%, 87.6%).
Step-by-step explanation:
Question a:
86.6% out of 3149, so:
0.866*3149 = 2727.
272 used at least one prescription medication.
Question b:
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 z-score that has a p-value of .
For this problem, we have that:
90% confidence level
So , z is the value of Z that has a p-value of
, so
.
The lower limit of this interval is:
The upper limit of this interval is:
For the percentage:
0.856*100% = 85.6%
0.876*100% = 87.6%.
The 90% confidence interval estimate of the percentage of adults aged 57 through 85 years who use at least one prescription medication is (85.6%, 87.6%).