A recent graduate school study of a random sample of 250 US manufacturing companies determined the average financial report preparation time was 68.04 days with a standard deviation of 35.74 days. Calculate to three decimal places the 95 percent confidence interval for the mean report prep time for all US manufacturing companies. [63.001, 72.008] [63.957, 75.568] [63.505, 72.414] [61.612, 74.468] [63.612, 72.468]

And the best option for this case would be

Step-by-step explanation:

Information given

represent the sample mean

population mean

s=35.74 represent the sample standard deviation

n=250 represent the sample size  

Confidence interval

The confidence interval for the mean is given by the following formula:

  (1)

The degrees of freedom are given by:

The Confidence level is 0.95 or 95%, and the significance and , and the critical value for this case woud be

And replacing we got:

And the best option for this case would be

y = 0.77(x)

step-by-step explanation:

the jacket retains this value after 23% cut or retains 77% of original value. plug original 87 jacket price for x and the remaining value should be y.

probability for j is 1/4

while

a is 1/6