You may need to use the appropriate appendix table or technology to answer this question.

A simple random sample of $50$ items from a population with $=6$ resulted in a sample mean of $34.($

$($a$)$ Construct a $90$ per cent confidence interval for the population mean, $.$

to

$($b$)$ Construct a $95$ per cent confidence interval for $.$

to

$($c$)$ Construct a $99$ per cent confidence interval for $.$

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