Confidence Interval

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Posted in: , on 21. Aug. 2007 - 02:07

Plz Help!!!!!!! I can't figure this out

Confidence interval for the population mean: Use of the t distribution

A corporation that maintains a large fleet of company cars for the use of its sales staff is interested in the mean distance driven monthly per sales person. The following table gives the monthly distances in miles driven by a random sample of sales persons:



Based on this sample, find a confidence interval for the mean number of miles driven monthly by members of the sales staff, assuming that monthly driving distances are normally distributed. Then complete the table below.

Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place.

**Questions from the above scenario**

What is the lower limit confidence level?

What is the upper limit confidence level?

95% Confidendence Limits

Posted on 21. Aug. 2007 - 01:35


Arithmetic mean in milesxbar2163

95% Confidence range

Lower limit in miles95% LCR2080

Upper Limit in miles95% UCR2245

95% Confidence interval in miles95% CI82

95% Confidence interval in %rel95% CI3.8

Variance in miles^2var(x)29259

Standard deviation in milessd(x)171

Coefficient of variation in %relCV7.9

Number of measured valuesn19

Variance of central value in milesvar(xbar)1540

Standard deviation in milessd(xbar)39

Degrees of freedomdf18

Tabulated t-value at 5% probabilityt0.05;df2.10

Re: Confidence Interval

Posted on 21. Aug. 2007 - 08:31

Sounds like student strife.

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