The scores on a standardized mathematics test for 8th grade children in New York State form a normal distribution with a mean of u=70 and a standard deviation of o=10.
a. What proportion of the students in the state have scores less than x=75?
b. If samples of n=4 are selected from the population, what proportion of the samples will have means less than M=75?
c. If samples of n=25 are selected from the population, what proportion of the samples will have means less than M=75?