The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Courses » ap-stat

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

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

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Barrier, Robert

Posts: 12
Registered: 12/6/04
rounding z-scores
Posted: Jan 14, 1997 11:20 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

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

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.