Calculating xbar: P(Mu > xbar)=0.025, df=20, Muxbar=39.4, sigmaxbar=28.7

[zmike]

Homework Statement

Calculate the following:xbar
where P(Mu > xbar) = 0.025, df = 20, Muxbar = 39.4, sigmaxbar = 28.7

Homework Equations

t = (xbar - mu)/(s/sqrt n)

The Attempt at a Solution

I know that I can plug muxbar, t =2.086 using my table but I don't know about s.

muxbar is the mean of the samples so do I use the sigmaxbar since it's the SD of the mean of the samples? Is that the same as s?

WHAT IS the difference between muxbar and mu and xbar?

thanks

 

[lippyka]

!Muxbar is the mean of the samples, while mu is the population mean and xbar is the sample mean. To calculate xbar, you need to use the t-distribution formula: t = (xbar - mu)/(s/sqrt n) where s is the standard deviation of the sample and n is the number of samples. In this case, s = sigmaxbar, so you can substitute that in the formula and solve for xbar.