statistics
posted by helga .
what are the mean and standard deviation of a sampling distribution consisting of samples of size 16? these sameples were drawn from a population whose mean is 25 and who standard deviation is 5.
a. 25 and 1.25
b. 5 and 5
c. 25 and 5
d. 5 and 1.25
e. 25 and square root of 5
the standard deviations of SAT scores is 100 points. a researcher decides to take a sample of 500 students' scores to estimate the mean score of students in your state. what is the standard deviation of the sample mean?
a. 0.2
b. 4.47
c. 5
d. 100
e. can't determine without sample mean
what is the critical zvalue for an 85% confidence interval?
a. .8023
b. 1.44
c. 1.04
d. need population standard deviation
e. need sample size
which of the follow isn't necessary to compute the sample size appropriate for a given confidence level and margin of error?
a. sample mean
b. populatuion standard deviation or an estimate of standard deviation
c. critcal zvalue, z*
d. the margin of error m.
e. all of these values are neccessary

hi, u can solve it by this formula
S=√Σ(Xmean)

n1