Question

QUESTION 7 50 An algebra placement test was used to determine placement in mathematics courses. A sample of calculus students gave 50 scores. It is known 2 It is known 2 Xi x = 20 i=1 00, X;= 821. Use the sample i = 1 standard deviation as the population deviation. If you want to be captured in a 96% confidence interval with length equal to 4, what is the minimum sample size? 147.49551 QUESTION 8 A university's administrator proposes to do an analysis of the proportion of graduates who have not found employment in their major field one year after graduation. In previous years, the percentage averaged 9%. He wants the margin of error to be within 39 at a 99% confidence level. What sample size will suffice? 605.7324

I only need #'s 8 and 22, note 22 is not A and 8 is not 606

Answer 1

Question 8

Population proportion = p = 0.09

stanard error of proportion = sqrt [p * (1-p)/n] = sqrt [0.09 * 0.91/n]

Margin of error = 3% = 0.03

Critical test statistic for 99% confidence interval = 2.586

so here

0.03 = 2.586 * sqrt [0.09 * 0.91/n]

n = (2.586/0.03)² * 0.09 * 0.91

n = 603.7756

or n = 604

Question 22

Sample size = n = 10

Here degree of freedom = 10 - 1 = 9

Here it is asked that which of the following is not a 95% confidence interval of population mean $\mu$ .

Here option a is a 95% confidence interval. Option b, Option C, Option D are also 95% confidence interval but not a symmetric one.

But here the answer is option e as this is not a 95% confidence interval as 0.045 + 0.01 = 0.055 not equals to 0.05.

Here the question is tricky as it asked not a 95% confidence interval.