Canister vacuums are often rated according to their ease of use, noise level, emissions, cleaning ability, and length of the power cord. The length (in feet) of the electric cord on a canister vacuum is a random variable, X, with a uniform distribution on the interval [20, 30]. Suppose a canister vacuum is selected at random.
a. Carefully sketch a graph of the probability density curve for the random variable X.
b. What is the probability that the power cord has a length less than 22 feet?
c. What is the probability that the power cord has a length greater than 26 feet?
d. Find a value f such that 75% of all power cords have lengths greater than f feet.
A random sample of the rice production (in 1000 tons) per year in various provinces in China is given.25 Is there any evidence to suggest that the data are from a non-normal population?
The manager for the Wingate Inn claims the time it takes to make a room reservation over the phone is approximately normally distributed with mean four minutes and standard deviation 45 seconds. Suppose a call placed to the inn to make a room reservation is selected at random.
a. What is the probability that it will take less than three minutes to make the reservation?
b. What is the probability that it will take between 31 2 and 41 2 minutes to make the reservation?
c. Find the first and the third quartile times.
d. Suppose it takes seven minutes to make the reservation. Is there any evidence to suggest the inn’s claim ( m = 4 minutes) is false? Justify your answer.