W-15=-4w−15=−4
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d) 65.9 in < μ < 67.1 in.

Step-by-step explanation:

Given that a 99% confidence interval (in inches) for the mean height of a population is 65.7 < μ < 67.3

Mean = average of 65.7 and 67.3 =

i.e. here margin of error =

For 99% confidence interval critical value is 2.58

Hence std deviation =

For 95% confidence interval critical value is 1.96

Margin of error =

Hence confidence interval =

d) 65.9 in < μ < 67.1 in. is right