I'm having trouble reading the z* table for confidence interval testing.
Here's the problem I have:
1.A city assessor needed an estimate of the mean income per household. A random sample of 40 households in the city showed a mean income of $29, 400 and a standard deviation of $6,325. Find a 99% confidence interval for the mean income per household. Can the assessor conclude that the mean income per household has increased over last years figure of $25,100?
I know HOW to solve the problem, I just cannot figure out how to find the z* value thats needed for the formula. Here is the chart I am using:
http://lilt.ilstu.edu/dasacke/eco148/zta…
Here's the problem I have:
1.A city assessor needed an estimate of the mean income per household. A random sample of 40 households in the city showed a mean income of $29, 400 and a standard deviation of $6,325. Find a 99% confidence interval for the mean income per household. Can the assessor conclude that the mean income per household has increased over last years figure of $25,100?
I know HOW to solve the problem, I just cannot figure out how to find the z* value thats needed for the formula. Here is the chart I am using:
http://lilt.ilstu.edu/dasacke/eco148/zta…
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Just Me
You are using the wrong table ... you need to use a t-table because you are given a "sample" standard deviation.
With 39 d.f. , t* = 2.708
Hope that helps
You are using the wrong table ... you need to use a t-table because you are given a "sample" standard deviation.
With 39 d.f. , t* = 2.708
Hope that helps