# Confidence Interval

It is desired to estimate which of the two soft drinks, Coke or Pepsi, UCLA students prefer. A random sample of 167 UCLA students produced the following 95% confidence interval for the proportion of UCLA students who perfer Pepsi: (.344, .494) A. Is this a large enough sample for this analysis to work? aa) Yes, since N=167, which is 30 or more. bb) Yes, 95% is a very high confidence. cc) No. dd) Not enough information. I think the answer is aa), but correct me if i am wrong. B. Which of the following is a practical interpretation of this 95%confidence interval? aa) 95% confident that the number of UCLA students who prefer Pepsi is .344 to .494 bb)The probability of 95% of UCLA students in this sample preferring Pepsi is between .344 and .494 cc) 95% confident that the proportion of all UCLA students who prefer Pepsi is between .344 and .494 C. If you are asked to estimate the population proportion of UCLA students preferring Pepsi, which of the following is the best estimate? aa) 34.4% bb) 49.4% cc) 50% dd) 41.9% Please explain or show how you derived your solution and add any comments that might be helpful.

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A) Yes , N= 167 is a large enough sample to work.

B) bb)The ...

#### Solution Summary

It is desired to estimate which of the two soft drinks, Coke or Pepsi, UCLA students prefer. A random sample of 167 UCLA students produced the following 95% confidence interval for the proportion of UCLA students who perfer Pepsi: (.344, .494) A. Is this a large enough sample for this analysis to work? aa) Yes, since N=167, which is 30 or more. bb) Yes, 95% is a very high confidence. cc) No. dd) Not enough information. I think the answer is aa), but correct me if i am wrong. B. Which of the following is a practical interpretation of this 95%confidence interval? aa) 95% confident that the number of UCLA students who prefer Pepsi is .344 to .494 bb)The probability of 95% of UCLA students in this sample preferring Pepsi is between .344 and .494 cc) 95% confident that the proportion of all UCLA students who prefer Pepsi is between .344 and .494 C. If you are asked to estimate the population proportion of UCLA students preferring Pepsi, which of the following is the best estimate? aa) 34.4% bb) 49.4% cc) 50% dd) 41.9%

Please explain or show how you derived your solution and add any comments that might be helpful.