Question

a random variable is defined as a process or variable with a numerical outcome. which of the following are random variables?
i. the amount of rain, in inches, that will fall next friday in dallas, tx.
ii. the major of a randomly drawn student from arizona state university.
iii. the number of books purchased next year by your local library.
oi only
oii only
oiii only
oi and iii
oii and iii
oi, ii, and iii

Explanation:

• i. The amount of rain is a numerical outcome that is uncertain before next Friday, so it's a random variable.
• ii. The major of a student is a non - numerical categorical variable, not a random variable as defined (with a numerical outcome).
• iii. The number of books purchased is a numerical outcome that is unknown in advance, so it's a random variable.

Answer:

D. i and iii