Question

WILL FAN AND MEDAL


The standard normal curve shown below models the population distribution of a random variable what proportion does not lie between the two z-scores of the diagram?
A 0.3097
B 0.3025
C 0.3148
D 0.3310
E 0.3234
http://assets.openstudy.com/updates/attachments/51925796e4b0e9fd532950fe-amandaplease-1368545194919-76438b2856b74a45a1111049dde24c2e.gif

Answer 1

@jim_thompson5910

Answer 2

@kropot72

Answer 3

Do you know how to use a standard normal distribution table?

Answer 4

No

Answer 5

Are you expected to use technology, such as a statistical graphing calculator, to solve this?

Answer 6

Not really sure. They just expect me to know the answer.

Answer 7

I can guide you in the use of a standard normal distribution table such as the one here:
http://www.math.bgu.ac.il/~ngur/Teaching/probability/normal.pdf
Shall we continue?

Answer 8

Yeah sure

Answer 9

First use the table to find the cumulative probability when z = -1.3.
Find -1.3 in the left hand column, then go to the value beside -1.3 in the next column.
What do you get?

Answer 10

0.0968

Answer 11

Good work! Now find the cumulative probability for z = 0.75. When you find 0.7 in the left hand column, you will need to move across to the column headed 0.05 to read the probability value for 0.75.

Answer 12

0.7734

Answer 13

Correct again! Now we can find the proportion that lies between the two given z-scores by simple subtraction:
Hatched proportion = 0.7734 - 0.0968 = ?
When you have calculated this we can proceed to the final step.

Answer 14

0.6766

Answer 15

Correct. Now we have found the proportion that is hatched, we can find the required proportion that lies outside the hatched area by subtracting again. This is because the total area under the curve is 1.0000.
Proportion not lying between the two z-scores = 1.0000 - 0.6766 = ?

Answer 16

0.3234

Answer 17

You are correct! Good work :)

Answer 18

Yaaaay thank you

Answer 19

You're welcome :)