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.

a. i only
b. ii only
c. iii only
d. i and iii
e. ii and iii
f. i, ii, and iii

d. i and iii

Step-by-step explanation:

Notice that the definition provided states that the outcome needs to be numerical in order for a variable to be deemed a random variable:

i. The amount of rain is described in inches (i.e. 1.5 in; 2.0 in) and thus may be considered a random variable

ii. The major of a student is not quantitative as it is a descriptive variable (i.e. Arts; Psychology) and thus is not a random variable

iii. The number of books purchased is a numeric quantity (i.e. 15 books) and may be considered a random variable

Therefore, the answer is d. i and iii

step-by-step explanation:

i found the life tables for the year 2012. 

life table of males at age 30. probability of dying between ages x and x+1

total population:  

29–30 . . . . . . . . . . . . 0.001030

30–31 . . . . . . . . . . . . 0.001061

males:  

29–30 . . . . . . . . . . . . 0.001420

30–31 . . . . . . . . . . . . 0.001448

white population

29–30 . . . . . . . . . . . . 0.001005

30–31 . . . . . . . . . . . . 0.001037

white males

29–30 . . . . . . . . . . . . 0.001372

30–31 . . . . . . . . . . . . 0.001399

non hispanic white population

29–30 . . . . . . . . . . . . 0.001083

30–31 . . . . . . . . . . . . 0.001116

non hispanic white males

29–30 . . . . . . . . . . . . 0.001477

30–31 . . . . . . . . . . . . 0.001503

jacob, non hispanic white male. 30 years old.

probability that jacob lives to be 30 years old. 

since the given probabilities are probabilities of dying, i think we simply subtract it from 1 to get the probability of living. we will use the probability of non hispanic white male.

                                          probability of living to be 30 y.o.

29 - 30 : 1 - 0.001477 = 0.998523

30 - 31 : 1 - 0.001503 = 0.998497