Question

Normal distribution ??????

Answer 1

huh?

Answer 2

I need help with normal distribution please

Answer 3

define it or something

Answer 4

The question says a normal distribution has a mean of 18 and a standard deviation of 3. Find the probability that a randomly selected x-value from the distribution is in the given interval.

1. Between 18 and 21
2. Between 12 and 18
3. At least 27
4. At most 12

Answer 5

Please help 😔

Answer 6

@gswag98

Answer 7

these type of probability questions I don't know

Answer 8

Use \(\sf z=\dfrac{x-\mu}{\sigma}\) to convert the value to a standard normal distribution N~(0,1) so you can use z-tables.

for example,

1. Between 18 and 21, we know 18 is the mean so, z=0

we wanna find P(18<x<21)



so we only work with 21, \(z=\dfrac{21-18}{3}=1\) so this is now P(0<z<1)

from z-table, z=1, P=0.3413

So P(18<x<21)=P(0<z<1)=0.3413-0=0.3413