1. A population of values has a normal distribution withμ=72μ=72 and σ=3.1σ=3.1. You intend to draw a random sample of sizen=154n=154.

Find the probability that a single randomly selected value isbetween 71.3 and 71.7.
P(71.3 < X < 71.7) =

Find the probability that a sample of size n=154n=154 israndomly selected with a mean between 71.3 and 71.7.
P(71.3 < M < 71.7) =

Enter your answers as numbers accurate to 4 decimal places.Answers obtained using exact z-scores or z-scoresrounded to 3 decimal places are accepted.

2.

In a recent year, the Better Business Bureau settled 75% ofcomplaints they received. (Source: USA Today, March 2, 2009) Youhave been hired by the Bureau to investigate complaints this yearinvolving computer stores. You plan to select a random sample ofcomplaints to estimate the proportion of complaints the Bureau isable to settle. Assume the population proportion of complaintssettled for the computer stores is the 0.75, as mentioned above.Suppose your sample size is 278. What is the probability that thesample proportion will be at least 5 percent more than thepopulation proportion?

Note: You should carefully round any z-values you calculate toat least 4 decimal places to match wamap's approach andcalculations.

Answer =

(Enter your answer as a number accurate to 4 decimalplaces.)

3.

Business Weekly conducted a survey of graduates from 30 top MBAprograms. On the basis of the survey, assume the mean annual salaryfor graduates 10 years after graduation is 165000 dollars. Assumethe standard deviation is 32000 dollars. Suppose you take a simplerandom sample of 90 graduates.

Find the probability that a single randomly selected salary thatdoesn't exceed 169000 dollars.
Answer =

Find the probability that a sample of size n=90n=90 is randomlyselected with a mean that that doesn't exceed 169000 dollars.
Answer =

Enter your answers as numbers accurate to 4 decimal places.

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