Question

in a certain region, the ages of licensed drivers is normally distributed with a mean of 44.5 years and a standard deviation of 9,1 years. Find the percentage that a randomly selected driver is younger than 25

Answer 1

How to make

44.5 years and a standard deviation of 9,1 years

into a standard normal? Do you have the formula?

Answer 2

I dont know the formula...that is the problem. I have all these notes and i am so lost..

Answer 3

Okay

z = (x - mean)/ standard deviation

I would start a new page of notes and keep this formula in a safe place.

Answer 4

i tried that but that doesnt give me the right answer

Answer 5

the answers are
a 1.6%
b 2.7%
c 4.9%
d 88.4%

Answer 6

z = (25 - 44.5)/9 = -2.17

What do we do next?

Answer 7

I have no idea :/

Answer 8

Hmm. Are you okay with the formula? Did you get the same answer?

Answer 9

yes, well i got - 2.14 i did 25-44.5 seperate then divided by 9.1

Answer 10

Ohh,

9,1

meant

9.1?

Answer 11

Do you have your z-table with all of those numbers in it?

Answer 12

i never got a z table..i dont even know what that means

Answer 13

i was absent 3 days i had to go to Ohio for an emergency

Answer 14

Ohh, hope everything is okay. Google has a z-table if you missed school on that day

https://www.google.com/search?q=z-table&hl=en&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=PCoCT9zSPKaciQLswMDQDg&sqi=2&ved=0CCkQsAQ&biw=1024&bih=613

Answer 15

thank you..i dont understand it at all..but thanks anyways

Answer 16

did you look at one of the charts? We need to find 2.14 using the outside of the chart?