Which of the following is a requirement for a random sample?

A. Every individual has an equal chance of being selected.

B. The probabilities cannot change during a series of selections.

C. There must be sampling with replacement.

D. Each of the other 3 choices are correct.

You are instructed to square each score and subtract four points from the sum of these squared scores. How would this set of instructions be expressed in summation notation?

A. X²- 4

B. (X)² - 4

C. (X - 4)²

D. (X²) -4

Which statement accurately describes the proportions in the tails of a normal distribution?

A. Proportions in both the left-hand and right-hand tails tend to be relatively small.

B. Proportions in both the left-hand and right-hand tails tend to be relatively large.

C. The proportion in the left-hand tail is larger than the proportion in the right-hand tail.

D. The proportion in the right-hand tail is larger than the proportion in the left-hand tail.