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?

... General rules for calculating probabilities Type of probability Identification Computation method Marginal Probability of Number of events under some stand ...

... Three tables listed below show random variables and their probabilities. However, only one of these is actually a probability distribution. (a) Which is it? ...

Probability of dice. Please help with the following problem. Compute the probabilities for each of the following when you throw five six-handed dice. ...

... trials, but with unequal Probabilities of success from trial to trial. Assume n = 2 independent trials are to be performed; the probability of success for the ...

Probability Distribution Questions: Normal, Poisson using Excel worksheet functions. ... Reject region Lower limit 19.8 Upper limit 20.3. Probability of reject. ...

... Stafford 9. The probability that a male will be color blind is 0.42 .Find the probabilities that, in a group of 53 men, the given conditions will be true a ...

... Explain using probabilities. No the events are not independent when 2 events are independent, probability of both occurring [P(A and B) = P(A) * P(B ...

... c) What is the probability the random variable will assume a value between 40 ... that z is a standard normal random variable, compute the following probabilities. ...

... 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 ...