Given a population that is normally distributed with a = 65 and = 3, the probability of randomly ...

Given a population that is normally distributed with a
   = 65 and  = 3, the probability of randomly selecting an object greater than 68 is:
  1.0.5000
  2.0.6827
  3.0.8413
  4.0.1587

Q. 2

Given a population that is normally distributed with a  = 65 and  = 3, calculate the z-score for an of 68 from a sample of size 9.
  1.1
  2.-1
  3.3
  4.-3

Q. 3

Ball-bearings are manufactured such that their mean diameter is 2 inches and their standard deviation is 0.5 inches. Many samples of size 25 are randomly selected and their means are calculated. The distribution of these sample means should:
  1.be exactly the same as the parent population.
  2.have a similar measure for central tendency but much more dispersed.
  3.have a similar measure for central tendency but much less dispersed.
  4.randomness makes it too difficult to predict.

Q. 4

As the sample size increases the ________.
  1.Standard error increases and the sampling distribution of sample means becomes shorter and wider.
  2.Standard error increases and the sampling distribution of sample means becomes taller and thinner.
  3.Standard error decreases and the sampling distribution of sample means becomes shorter and wider.
  4.Standard error decreases and the sampling distribution of sample means becomes taller and thinner.

Q. 5

A variable that follows a binomial distribution with n =10 and p = 0.2 would have a distribution that is:
  1.symmetrical and rectangular
  2.right-skewed
  3.left-skewed
  4.symmetrical and mounded

Q. 6

Which of the following is true when sampling, with replacement, from the distribution 1,2,3,4,5,6 with sample sizes of two:
  1.a mean of any two being 4 is fairly common
  2.all of the sample means will be equal.
  3.a mean of any two being 3.5 is impossible.