# Confidence Interval

1. Nancy Joon, Inc. has 1500 employees. A simple random sample of 81 employees was selected and the individuals I the sample were asked how much they contribute monthly to their retirement accounts. The mean amount for the sample was $150 with a standard deviation of $45. Develop an approximate 95% confidence interval for the mean.

2. From a population of 2000 accounts receivable, a simple random sample of 120 accounts is selected. Thirty-six of the accounts in the sample were overdue. Develop an approximate 95% confidence interval for the proportion of overdue accounts in the population.

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Nancy Joon, Inc. has 1500 employees. A simple random sample of 81 employees was selected and the individuals I the sample were asked how much they contribute monthly to their retirement accounts. The mean amount for the sample was $150 with a standard deviation of $45. Develop an approximate 95% confidence interval ...

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