The sample proportion has an approximately normal distribution, with the mean being the population mean and the standard deviation (i.e. the standard error of the sampling proportion) equal to
SE = sqrt(p*q/n) where p is the population proportion q is 1-p, and n is the sample size.
<span>(Typically, for a confkdence interval, the sample proportion and its complement are substituted for p and q.) </span>
The margin of error will be Zc*SE, where Zc is the critical value of Z for the level of confidence required. The confidence interval, then, will be the sample proportion, plus or minus the margin of error.
For a 90% confidence interval, Zc is 1.645.
<span>So the margin of error is 1.645 * sqrt(.9*.1/400), roughly .025. So your confidence interval would be around [.875, .925]
The best and most correct answer among the choices provided by your question is the second choice or letter C which is 3%.
I hope my answer has come to your help. Thank you for posting your question here in Brainly.</span>
Answer:
0,1,2,3,4,5
Step-by-step explanation:
You can not buy more than 5 books because you'd have a negative amount of money. So 0,1,2,3,4,5 are the possible values for b.
I think the correct answer your looking for is D) 9
The percentage that the number of airlines with an average airplane age of 14 is less than the number of airlines with an average airplane age of 11 is:
B. 20%.
<h3>What is a percentage?</h3>
The percentage of an amount a over a total amount b is given by a multiplied by 100% and divided by b, that is:

The percentage of airlines with an average age of 14 years is:

The percentage of airlines with an average age of 11 years is:

The difference is:
33.33% - 13.33% = 20%.
Hence option B is correct.
More can be learned about percentages at brainly.com/question/10491646
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