The following examples are experiments and their associated random variables. In each case identify the values the random variable can assume and state whether the random variable is discrete or continuous:
EXPERIMENT RANDOM VARIABLE (x)
a.) Take a 20-question examination Number of questions answered correctly
b.) Observe cars arriving at a tollbooth Number of cars arriving at the tollbooth for 1 hour
c.) Audit 50 tax returns Number of returns containing errors
d.) Observe an employee’s work Number of non-productive hours
for 8 hours
e.) Weigh a shipment of goods Number of pounds
21. For the standard normal random variable z, compute the following probabilities:
a.) P(0 ≤ z ≤ 0.83)
b.) P(− 1.57 ≤ z ≤ 0)
c.) P(z > 0.44)
d.) P(z ≥ 20.23)
e.) P(z < 1.20)
f.) P(z ≤ 20.71)