Math Is Fun Forum

Mikky

Guest

Finding the equivalent z-score for Q1 and Q3?

Am I doing this correctly?

I wasn't there when we learnt this, so I am guessing how to do it. So if my question doesn't entirely make sense, that's not my fault because that's what it's asking. :-)
I want to find the equivalent z-score for Quartile 1 and for Quartile 3.

Where the mean is 79.125 and the sample standard deviation is 13.3285648 (no rounding here). Q1 value is 69 and Q3 is 90. (/ means divide)

so, for Q1. z score = 69 - 79.125 / 13.3285648 = -0.7596....

and for Q3 z score = 90 - 79.125 / 13.3285648 = 0.8159....

Am I correct in saying that the z score equivalent for Q1 is -0.7596, and the z score equivalent for Q3 is 0.8159???

Cheers :-)

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Finding the equivalent z-score for Q1 and Q3?

Hi;

That is what I am getting too, based on what you are given to work with.

The only thing I do not like is the statements that Q1 = 69 and Q3 = 90. That is not very close to the answers.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.