Find the indicated area under the standard normal curve. Between z=-1.35 and z=1.35.

Question

I need to know how to do it step by step so that I can do the other problems.

Answer 1

You have to have a table of z-scores,

 

If you go to the NEGATIVE z-scores Table and go down to -1.3, then straight across to the column labeled .05, then the number that you see in the table at that point is .0885. That is the area of the standard curve all the way from the left to z= -1.35.

 

Now go to the POSITIVE z-scores Table, go down to 1.3, then across to the column headed .05, and the number you see is .9115. That is the area of the standard curve all the way from the left to z = 1.35.

 

So the area between the two z-values will be .9115 - .0885 = .8230   In other words, that section occupies 82.30% of the area of the standard curve.