A simple random sample of 64 observations was taken from a large ...

[Lisaclaire]

A simple random sample of 64 observations was taken from a large population. The population standard deviation is 120 . The sample mean was determined to be 320 . The standard error of the mean is _____.
 a. 1.875
  b. 40
  c. 5
  d. 15

Question 2

Twenty-five percent of the employees of a large company are minorities. A random sample of 7 employees is selected.
 a. Define the random variable in words for this experiment.
  b. What is the probability that the sample contains exactly 4 minorities?
  c. What is the probability that the sample contains fewer than 2 minorities?
  d. What is the probability that the sample contains exactly 1 non-minority?
  e. What is the expected number of minorities in the sample?
  f. What is the variance of the minorities?

[epscape]

Answer to Question 1

d

Answer to Question 2

a. x = the number of minority employees out of 7 or
y = the number of non-minority employees out of 7
b. .0577
c. .4449
d. .0013
e. 1.75
f. 1.3125

[Lisaclaire]

Great answer, keep it coming

[bulacsom]

Wow, this really help