Homework Help: statistics

Posted by Sunshine on Thursday, March 21, 2013 at 12:44am.

Scores on a visual perception test are normally distributed with a mean of 2020 and a standard deviation of 250.

a)If one subject is randomly selected and tested, find the probability of a score greater than 1800
b)if 50 subjects are randomly selected and tested fid the probability that the sample mean is between 2000 and 2100

statistics - PsyDAG, Thursday, March 21, 2013 at 1:01pm
a) Z = (score-mean)/SD

b) Z = (score-mean)/SEm

SEm = SD/√n

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions/probabilities related to the Z scores.

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