Question

The measured weights of 1,000 men in a certain village follow a normal distribution with a mean of 150 pounds and a standard deviation of 15 pounds. Which sentence most closely summarizes the data?

About 160 people weigh more than 165 pounds.

About 320 people weigh more than 165 pounds.

About 320 people weigh less than 165 pounds.

About 640 people weigh less than 165 pounds.

Answer 1

The weight 165 pounds is 1 standard deviation above the mean weight of 150 pounds. Therefore the z-score for 165 pounds is 1.0. The cumulative probability of weights less than 65 pounds can be found from a standard normal distribution table such as the one here:
http://lilt.ilstu.edu/dasacke/eco148/ztable.htm
When you have found the cumulative probability of weights less than 165 pounds multiply by 1000 to find approximately how many people weigh less than 165 pounds.
The correct choice of answer can then be found.

Answer 2

@Nenaa105 Do you understand how to solve it now? If not, please ask for help on what is not clear to you.

Answer 3

no im confused, could you show me how to solve it step by step please

Answer 4

Have you looked at the link that I posted?

Answer 5

yes

Answer 6

z values in the table are in the left-most column. When z is 1.0 what value is in the column next to the z value of 1.0?

Answer 7

z .00 .01 .02 .03 .04 .05 .06 .07 .08 .09
0.0 .5000 .5040 .5080 .5120 .5160 .5199 .5239 .5279 .5319 .5359
0.1 .5398 .5438 .5478 .5517 .5557 .5596 .5636 .5675 .5714 .57

Answer 8

.5398

Answer 9

No. It is .8413

Answer 10

So now multiply 0.8413 by 1000 to find approximately how many people weigh less than 165 pounds.
What you you get?

Answer 11

oh ok ok i got it thank you

Answer 12

No problem! Your welcome!!:)

Answer 13

and how do you solve for z?

Answer 14

What was your answer, so I can help you further?

Answer 15

841.3

Answer 16

wait but thats too much

Answer 17

Do you not understand?

Answer 18

Anyways: Since you got 841.3 Now subtract 841 from 1000 to find approximately how many people weigh more than 165 pounds.

Answer 19

What is it?