Question

The standard normal curve shown here is a probability density curve for a continuous random variable. This means that the area underneath the entire curve is 1. What is the area of the shaded region between the two z-scores indicated in the diagram?

A. 0.1131
B. 0.7864
C. 0.1151
D. 0.7068
E. 0.7188

Answer 1

Z=-1.26 and z= -0.88

Answer 2

Are you sure these are the correct z-scores given for this problem? I got a probability even smaller than your smallest option.

Answer 3

It's only .88

Answer 4

Sorry!! And thank you!!!

Answer 5

Much better. Do you have a z-score table handy?

Answer 6

If not here is both a left and right tail z-score table
http://www.sixsigmastudyguide.com/wp-content/uploads/2014/04/z-table.jpg

Answer 7

So sorry my iPad keeps crashing

Answer 8

So to find the area between the 2 z-scores, you want to find the area to the left of .88 which is the graph of left .88 and subtract the area that is left of -1.26 as seen in the graphs attached.

Answer 9

How do you post pictures??

Answer 10

That way you will find the area between the two z-scores like in the graph between -1.26 and .88

Answer 11

I'm generating the images, saving them to my computer, then attaching a file in the text.

Answer 12

Well crap haha

Answer 13

So taking the values from the table I posted first we know that the area left of .88 = .8106 and the area left of -1.26 = .1038

Answer 14

So what would you do to get the final answer?

Answer 15

Um, I stated that in the comment where I posted two graphs

Answer 16

So subtract?

Answer 17

Yes

Answer 18

Would it be D

Answer 19

Yes

Answer 20

Awesome!!!!

Answer 21

I made you a graph to show you were right