The Professor's Response

Hello Professor,

I am trying to do Homework Problem 40 for Section 7.4. I can't seem to figure out how to use it with Z instead of T. Can you please explain how to do this problem?

Thank you

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Professor McGukian

Hi Genessys,

Here is a video explaining the problem:

 

Professor McGukian

Just to summarize what the video shows: the first step here is to check if n is greater than 30.  If it is, we find Za/2 not ta/2. Since, we are finding Za/2, we do not need to worry about the degrees of freedom.  We go to the t-table looking up a/2 in the top row, then we go straight to the bottom of that 0.01 row where the Za/2 value is located. 

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