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IHP 525 Quiz Two

A telephone survey uses a random digit dialing machine to call subjects. The random digit dialing machine is expected to reach a live person 15% of the time.

True or False: Each call is an independent random event.

In two attempts, what is the probability of achieving……

exactly two successful calls? (success = reach a live person)

one success and one failure (in any order)?

The prevalence of a trait is 76.8%. In a simple random sample of

*n* = 50, how many individuals are expected to exhibit this characteristic and what is the corresponding standard deviation of this estimate?

Linda hears a story on National Public Radio stating that one in six eggs in the United States are contaminated with

*Salmonella*. If

*Salmonella* contamination occurs independently within and between egg cartons and Linda makes a three egg omelet, what is the probability that her omelet will contain at least one

*Salmonella* contaminated egg?

Suppose that heights of 10-year old boys vary according to a Normal distribution with µ = 138 cm and σ = 7 cm. What proportion of 10-year old boys is less than 140 cm in height?

A survey selects a simple random sample of

*n* = 500 people from a town of 55,000. The sample shows a mean of 2.3 health problems per person. Based on this information, say whether each of the following statements is

*true* or

*false*. Explain your reasoning in each instance. No calculations necessary.

It is reasonable to assume that the number of health problems per person will vary according to a normal distribution.

It is reasonable to assume that the sampling distribution of the mean will vary according to a normal distribution.

A simple random sample of 18 male students at a university has an average height of 70 inches. The average height of men in the general population is 69 inches. Assume that male height is approximately normally distributed with σ = 2.8 inches. Conduct a two-sided hypothesis test to determine whether the male students have heights that are significantly different than expected. Show all hypothesis testing steps.

True or false? The

*p*-value refers to the probability of getting the observed result or something more extreme assuming the null hypothesis.