18. According to an IRS study, it takes an average of 330 minutes for taxpayers to prepare, copy, and electronically file a 1040 tax form. A consumer watchdog agency selects a random sample of 40 taxpayers and finds the standard deviation of the time to prepare, copy, and electronically file form 1040 is 80 minutes.

a. What assumption or assumptions do you need to make about the shape of the population?
b. What is the standard error of the mean in this example?
c. What is the likelihood the sample mean is greater than 320 minutes?
d. What is the likelihood the sample mean is between 320 and 350 minutes?
e. What is the likelihood the sample mean is greater than 350 minutes?

... 4. If two events are mutually exclusive, we can _____ their probabilities to determine the union probability. A. Divide B. Add C. Multiply D. Subtract. ...

... mutually exclusive events then you need to calculate all three probabilities in the ... the sample mean (which is the same thing as the probability distribution of ...

... The probability mass function is simple the probabilities for each event: (1.31) The mean is: (1.32) Note that since the mass function is constant (uniformly ...

... b. Assign reasonable probabilities to the simple events. ... c. Find the probability that an active-duty military. ___. (Round person is an officer. ...

... b. Assign probabilities to the sample points in part a. c. Find the probability of each of the following events: A = {3 showing on each die} B = {sum of two ...

... Normal Probabilities. Common Data Mean 50000 Standard Deviation 3500 Probability for a Range From X Value 40000 To X Value 60000 Z Value for 40000 -2.857143 Z ...