# Thread: Quartiles in a normal Distribution

1. ## Quartiles in a normal Distribution

I cannot figure out how the Z score comes near 0.68 the Table given to me in my textbook gives the z score for 0.75 as 0.77. What have I done wrong?

2. ## Re: Quartiles in a normal Distribution

I've moved this post out of the 2013 thread you initially posted it in - it's usually better to just post a new question in a new thread rather than reviving an old one.

Re your question: You will probably need to expand and explain what you're asking here.

3. ## Re: Quartiles in a normal Distribution

I am trying to find the value of the IQR for the standard Normal distribution. I know that the final answer is 1.3490, but I am confused how to get there. The result I get using the table given to me gives a completely different number. I would have to take the Z score of 0.45 to get the correct answer according to my table.. I am so lost

4. ## Re: Quartiles in a normal Distribution

An interquartile range (IQR) is the distance between the 1st quartile (25th percentile) and third quartile (27th percentile). What are the 25th percentile and 75th percentile of the standard normal distribution?

5. ## Re: Quartiles in a normal Distribution

OP, CB meant third quartile = 75th percentile, if that was not implicit.

6. ## Re: Quartiles in a normal Distribution

Originally Posted by hlsmith
OP, CB meant third quartile = 75th percentile, if that was not implicit.
Thanks. I have no idea how I managed to type "27th!"

7. ## Re: Quartiles in a normal Distribution

I can guess how you did it, first you typed "2" then you typed "7". Side note, not completely related, there was just an article talking about why not to use quantile regression or quantiles for continuous predictors in regression, primarily related to reproducibility and generalizing results to other samples. Interesting and intuitive what thinking about it.

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