Suppose a uniform random variable can be used to describe the outcome of an experiment with the outcomes ranging from 20 to 90. What is the probability that this experiment results in an outcome less than 30?
A) 0.09 B) 0.14 C) 0.23 D) 1
Q. 2The number of violent crimes committed in a day possesses a distribution with a mean of 2.1 crimes per day and a standard deviation of 4 crimes per day.
A random sample of 100 days was observed, and the mean number of crimes for the sample was calculated. Describe the sampling distribution of the sample mean.
A) shape unknown with mean = 2.1 and standard deviation = 0.4
B) shape unknown with mean = 2.1 and standard deviation = 4
C) approximately normal with mean = 2.1 and standard deviation = 4
D) approximately normal with mean = 2.1 and standard deviation = 0.4
Q. 3A machine is set to pump cleanser into a process at the rate of 5 gallons per minute. Upon inspection, it is learned that the machine actually pumps cleanser
at a rate described by the uniform distribution over the interval 4.5 to 7.5 gallons per minute. Find the probability that between 5.0 gallons and 6.0 gallons are pumped during a randomly selected minute.
A) 1 B) 0 C) 0.67 D) 0.33
Q. 4Suppose a population has a mean weight of 180 pounds and a standard deviation of 25 pounds. A sample of 100 items is drawn from this population. What is the standard error of the mean?
A) 2.5 B) 1.8 C) 0.25 D) 18.0
Q. 5Suppose x is a uniform random variable with c = 10 and d = 50. Find the probability that a randomly selected observation is between 13 and 45.
A) 0.8 B) 0.20 C) 0.5 D) 0.80
Q. 6Suppose a population has a mean of 7 for some characteristic of interest and a standard deviation of 9.6. A sample is drawn from this population of size 64. What is the standard error of the mean?
A) 3.3 B) 0.15 C) 1.2 D) 0.7
Q. 7Suppose x is a uniform random variable with c = 10 and d = 90. Find the probability that a randomly selected observation exceeds 26.
A) 0.8 B) 0.2 C) 0.9 D) 0.1
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