The owner of a small store buys coats for $55.00 each answer part a and d
2 answers:
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Answer:
Step-by-step explanation:
Since the population standard deviation is unknown, and the sample standard deviation
, must replace it, the
distribution must be used for the confidence interval.
The sample size is n=8.
The degree of freedom is ,
.
With 95% confidence level, the (significance level) is 5%.
Hence with 7 degrees of freedom, . (Read from the t-distribution table see attachment)
The 95% confidence interval can be found by using the formula:
.
The sample mean is hours.
The sample sample standard deviation is hours.
We now substitute all these values into the formula to obtain:
.
We are 95% confident that the population mean is between 26.12 and 31.48 hours.
