A Study Is Going to Be Conducted in Which the Mean

question 43

Multiple Choice

A study is going to be conducted in which the mean of a lifetime of batteries produced by a certain method will be estimated using a 90% confidence interval.The estimate needs to be within +/- 2 hours of the actual population mean.The population standard deviation σ is estimated to be around 25.The necessary sample size should be at least _______.

• A)100
• B)21
• C)923
• D)35
• E)423

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