The waiting time (in minutes) between ordering and receiving your meal at a certain restaurant is exponentially distributed with a mean of 10 minutes.
The restaurant has a policy that your meal is free if you have to wait more than 25 minutes after ordering. What is the probability of receiving a free meal?
A) 0.082085 B) 0.329680 C) 0.670320 D) 0.917915
Q. 2A random sample of 15 crates have a mean weight of 165.2 pounds and a standard deviation of 13.5 pounds. Construct a 95 confidence interval for the population standard deviation .
Assume the population is normally distributed, and round to the nearest hundredth when necessary.
A) (97.69, 453.3 ) B) (10.38, 19.71 ) C) (9.88, 21.29 ) D) (2.69, 5.79 )
Q. 3Suppose the candidate pool for two appointed positions includes 6 women and 9 men. All candidates were told that the positions were randomly filled. Find the probability that two men are selected to fill the appointed positions.
A) .143 B) .160 C) .360 D) .343
Q. 4Identify the factors and levels.
What will be an ideal response?
Q. 5Suppose that 4 out of 12 liver transplants done at a hospital will fail within a year. Consider a random sample of 3 of these 12 patients. What is the probability that all 3 patients will result in failed transplants?
A) .296 B) .333 C) .018 D) .037
Q. 6The mean systolic blood pressure for a random sample of 28 women aged 18-24 is 115.2 mm Hg and the standard deviation is 13.1 mm Hg.
Construct a 90 confidence interval for the standard deviation , of the systolic blood pressures of all women aged 18-24. Round to the nearest hundredth when necessary.
A) (11.23, 15.99 ) B) (10.22, 18.34 ) C) (10.59, 16.54 ) D) (10.75, 16.94 )
Q. 7The time (in years) until the first critical-part failure for a certain car is exponentially distributed with a mean of 3.4 years. Find the probability that the time until the first critical-part failure is less than 1 year.
A) 0.966627 B) 0.033373 C) 0.745189 D) 0.254811
Q. 8The time (in years) until the first critical-part failure for a certain car is exponentially distributed with a mean of 3.4 years. Find the probability that the time until the first critical-part failure is 5 years or more.
A) 0.506617 B) 0.229790 C) 0.493383 D) 0.770210
Q. 9If no estimate of p exists when determining the sample size for a confidence interval for a proportion, we can use .5 in the formula to get a value for n.
A) True B) False
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