Question 79663: Please show me step by step answers on how to solve the 4 problems. Thankyou. It will be greatly appreciated.
Question 1
A researcher wants to estimate the proportion of students at York College who will choose Computer Science as their major in Spring 2008. She wants to be within 5.3% of the actual popultaion proportion and have a 95% level of significance. In a preliminary survey of 42 students 29 said they wanted to take Computer Science in 2008. What is the minimum sample size that she will require? Round final answer up to the next whole number.
Question 2
A fast food restaurant claims that the mean waiting time is not equal to 3 minutes. A random sample of 45 customers revealed a mean waiting time of 3.3 minutes with a standard deviation of 0.7 minutes. Test the restaurants claim at a, a=0.05 level of significance. Assume that the population is normally distributed, and the population standard deviation is 0.7. Use the P-value method.
Question 3: Hypothesis Testing for Proportions.
A researcher at York claims that for Mathematics courses the proportion of grades B or higher was more than 33.0%. In a random sample of 100 grades issued in the year 2006 there were 27 F's, 15 D's, 22 C's, 14 B's, 22 A's. At a=0.10 test the researcher's claim.
Use "rejestion region" claim.
Question 4: Determining sample size
A. A large public university wants to estimate the average(mean) teaching experience of it's faculty. A preliminary random sample of 20 faculty yields a standard deviation of s=2.5 years.
The dean wants to be 95% confident that the sample mean does not have a maximum error of estimate of more than 1.6 years. (Hint: this is maximum error of estimate E). How large of a sample should she use? Use the preliminary sample sample standard deviation as an approximation of the population standard deviation. ROund up to the next whole number.
B. If she decides on a maximum error of estimate of 1.8years. and a level of significance of 95% how large of a sample should she use? Round up to next whole number.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A researcher wants to estimate the proportion of students at York College who will choose Computer Science as their major in Spring 2008. She wants to be within 5.3% of the actual popultaion proportion and have a 95% level of significance. In a preliminary survey of 42 students 29 said they wanted to take Computer Science in 2008. What is the minimum sample size that she will require? Round final answer up to the next whole number.
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margin of error formula:
E=z*sqrt[pq/n]
sqrt(n) = z*sqrt(pq)/E
sqrt(n) = 1.96sqrt([29/42][13/42])/0.053
sqrt(n) = 17.096
n=292 (this is the required sample size)
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Can't do any more now; have to run. Mail me back if
you need help with the other probs.
Cheers,
Stan H.
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