1.a. How large a sample should be selected so that the margin of error of estima

Question

1.a. How large a sample should be selected so that the margin of error of estimate for a 98% confidence interval for p is 0.045 when the value of the sample proportion obtained from a preliminary sample is 0.53? (Answer is n=668, but I don't know how)

b. Find the most conservative sample size that will produce the margin of error for a 98% confidence interval for p equal to 0.045.

2. For a binomial probability distribution, n=25 p=0.4.

a.Find the probability p(x is greater and equal to 8, less and equal to 13) by using the table of binomial probabilities

b. find the probability p(x is greater and equal to 8, less and equal to 13) by using the normal distribution as an approximation to the binomial distribution. What is the differece between this aprroximation and the exact probability calculated in part a?

3. According to the U.S. Census American Community Survey, 5.44% of workers in Portland, Oregon, commute to work on their bicycles. Find the probability that in a sample of 400 workers from Portland, Oregon, the number who commute to work on their bicycles is 23 to 27.

Explanation / Answer

1 a. p=0.53 and E=0.045

We know that E=z*sqrt(p(1-p)/n)

So n=z^2*p*(1-p)/E^2 where z=2.33

So n=668

b here p =0.5

So n=670

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.