Question

STATS Question~!
Let X be N(μ= 25, (σ^2)= 16). Determine the following probabilities:
(a.) P(22< X <26)
(b.) P(19< X<24)
(c.) P(X>23)
(d.) P(|X-25| <5)

Answer 1

standard deviation =4
(a)
P(22<x<26)=
P(-0.75<Z<0.75)=
1-2P(Z>0.75)

get P(Z>0.75) and u found part A

Answer 2

where did the -.75 and the 0.75 come from?

Answer 3

Z= \(\Huge \frac {x-μ}{σ}\)

Answer 4

\(\Huge \frac {22-25}{4}\)
and \(\Huge \frac {26-25}{4}\) oops it's 0.25

Answer 5

so it would be ((22-25)/4) which gives -0.75, but you show a 0.75, so you show both the value, and it's opposite?
unless you mean for the second value to be (26-25)/4= 0.25?

Answer 6

sorry sorry.....

Answer 7

oh ok lol XD
Thanks a lot~! :D

Answer 8

oh wait,
P(−0.75 ≤ Z ≤ 0.25) = P(Z ≤ 0.25) − P(Z ≤ −0.75) = 0.5987-0.2266 =
0.3721
^is that the correct answer?

Answer 9

Let X be N(μ= 25, (σ^2)= 16). Determine the following probabilities: P(|X-25| <5)

How would you deal with the absolute value in this part of the question?

Answer 10

P(|X-25| <5)=P(-5<X-25<5)

Answer 11

^ah ok, Thanks! :D