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Topic: rounding z-scores
Replies: 2   Last Post: Jan 14, 1997 9:06 PM

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Barrier, Robert

Posts: 12
Registered: 12/6/04
rounding z-scores
Posted: Jan 14, 1997 11:20 AM
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Hello, All....

Having just submitted a response which was intended to answer the question of
rounding, I now have one of my own.

I have not seen published any clear guidelines for rounding z-scores. When
computing a z-score, I tell my students, we round to two decimal places so
that we can use the table of standard normal probabilities.

But when answering the question "what is the z-score such that P(Z<z) =.95"
what is the rule? P(Z<1.64) = .9495 and P(Z<1.65) = .9505. Which is the
correct choice?

Is there a different response when answering the question "What must a
student score to be in the top 10%?" (I have told my classes that their
answer should give a score which guarantees that P(X<x) is at least .9000.)

I could sure use some guidance....

Thanks in advance.

--Bob

----------------------------------------------------
Bob Barrier
C. E. Jordan High School
6806 Garrett Road
Durham, NC 27707

barrier@jordan.durham.k12.nc.us





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