Question

X has a normal distribution.
μ=32
Variance=σ2
Given that the probability that X < 33.14 is 0.60406, find the variance to 2 d.p.

Answer 1

variance = \[\sigma^2\]

Answer 2

look up Z-value of 0.60406

Z = (33.14 -32)/s , where s^2 is variance

Answer 3

Sorry, the probability is 0.6406

Answer 4

which is 0.36 for z value

Answer 5

i meant you need the Z-value that corresponds to the probability of .6406
ok

Answer 6

0.36 = 1.14/s

--> s = 1.14/0.36

then square it to get variance

Answer 7

dumb cow how did u get that dp? did they give it to you?

Answer 8

display picture

Answer 9

Ah Ok. Why did you have to square it?

Answer 10

oh that...its the default icon that i just saved to paint and messed around with it

Answer 11

because variance = standard deviation ^2

Answer 12

Ah Ok. Thanks! :)

Answer 13

root variance=s.d