Question on confidence interval and sample size

Reference no: EM13106220

1) Suppose that 64 smokers were sampled. Assume the sample mean and the sample standard deviation remained the same ($20 and $5, respectively).

a. What is the 95% confidence interval estimate of u?

b. A research a firm a conducted a survey to determine the mean amount of steady smokers spend on cigarettes during a week. A sample of 49 steady smokers revealed that X = $20 and s= $5. What is the 95% confidence interval estimate of u?

Explain why this confidence interval is narrower than the one determined in the previous exercise.

Reference no: EM13106220

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