the z-score is the number of standard deviations (σ's) that a value lies from the mean
the z-score table gives the probability of a score's position in a normal distribution
eg. the table gives the mean (z-score, zero) a probability of .5
... half of the population lies below the mean
p = 1/3 for x<=0
... from the table ... zero is .43 σ below the mean
p(x<=1)=2/3
... from the table ... 1 is .43 σ above the mean
Suppose x is random variable with normal distribution (u,sigma^2) distribution and p(x<=0)=1/3 and p(x<=1)=2/3 what are the values of u and sigma? Please show me the steps to solve such a question
Thank you
6 answers
Thanks for the answer but I still dont get it how did you get the 0.43?
http://davidmlane.com/hyperstat/z_table.html
click scond circle
put in area = .3333
and area = .6667
and you will get that -.43 and + .43
which means the mean is halfway between 0 and 1 :)
put in area = .3333
and area = .6667
and you will get that -.43 and + .43
which means the mean is halfway between 0 and 1 :)
now if the distance from 0 to 1 is 2*.43 sigma, what is sigma?
Thanks alot I have tried coming up algebrically with 0.43 but still no luck there is formula like x-u/sigma but still cant use it any ideas?