Z Notation

prettylittlepixels

New member
Joined
Nov 15, 2013
Messages
32
Give the z notation, z(0.xxxx), for the following z-scores.

1.91= First I used the table to get .4719, which isn't right. Then I added .5 to get .9719, which isn't right, so is it .5-.4719= .0281?

-.75= Would this be .5+.2734= .7734?

1.06= .5-.3554= .1446?

-2.32= .5+.4898= .9898?

Do I add .5 to the z-score for negative numbers and subtract the z-score from .5 for positive values? I think this would be right because the portion I shaded on a sketch is different for positive and negative numbers.

Thanks! I also updated a few of the threads with the parts of the problems I was still struggling with. Thanks!
 
It depends on the table you are using. I don't know what it is.

When I toss these things into Mathematica I do so via z = CDF[NormalDistribution[0,1]][x]

So I don't know from adding or subtracting 0.5 from things. I'd have to see your table. Is there a link to the table you are using?

That's what I had originally thought too.

It's in my textbook. It's the areas of the standard normal distribution is what it's labeled as in my text. So first I calculated the answers as:

1.91= .4719

-.75= 2734

1.06= .3554

-2.32= .4898

When my professor said the above wasn't correct, I had asked if the following was correct:
1.91= .9719

-.75= .2266

1.06= .8554

-2.32= .4898

He said these values weren't correct either and told me to draw sketches (of the normal distribution).

That is how I came up with the following:

1.91= .5-.4719= .0281?

-.75= Would this be .5+.2734= .7734?

1.06= .5-.3554= .1446?

-2.32= .5+.4898= .9898?
 
Top