1 Find the mean and standard error of the sample means that

1. Find the mean and standard error of the sample means that is normally distributed with a mean of 10 and a standard deviation of 2 and a sample size of 25. S. Using the above distribution find the probability of a score less than 11.

Solution

(7) mean=10 (stay the same)

standard error =s/vn = 2/sqrt(25) =0.4

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(8) The probability is

P(X<11) = P((X-mean)/s <(11-10)/2)

=P(Z<0.5)

=0.6915 (from standard normal table)