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# Please help with my homework packet. I need to have it done and turned in before 5:00pm today.

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1. If you want to be 99% confident of estimating the population mean t0 within a sampling error of ±20 and the standard deviation is assumed to be 120, what sample size is required? 2. Given a population of yearly sales (in number of copies) of a national periodical at newsstands located in a particular state, indicate what the sampling distribution for samples of 25 would consist of. A. The sampling distribution is the average result from all possible samples of 25 sales figures. B. The sampling distribution is a representative collection of 25 samples, each containing 25 sales figures, selected without replacement. C. The sampling distribution is the distribution of the result for all possible samples of 25 sales figures. D. The sampling distribution is a representative collection of 25 samples, each containing 25 sales figures, selected with replacement. 3. If P(B)=0.3, P(A | B)=0.5, P(B)=0.7, and P(A | B)=0.9, find P(B | A). 4. If, in a random sample of 200 items, 44 are defective, what is the sample proportion of defective items? 5. The following set of data is from a sample of n=7. 2 3 5 9 11 11 15 a) Compute the range, variance, standard deviation, and coefficient of variation. b) Compute the Z scores. Are there any outliers? c) Describe the shape of the data set. 6. If n=300 and X=120, construct a 90% confidence interval estimate of the population proportion. 7. In a random sample of 72 people, 36 are classified as “ successful.” A. Determine the sample proportion, p, of “ successful” people. B. If the population proportion is 0.75, determine the standard error of the proportion. 8. If, in a (two-tail) hypothesis test, the p-value is 0.0126, what is your statistical decision if you test the null hypothesis at the 0.02 level of significance? 9. Determine the upper-tail critical value t α/ 2 in each of the following circumstances. a. 1-a=0.90, n=40 d. 1-a=0.90, n=62 b. 1-a=0.95, n=40 e. 1-a=0.99, n=10 c. 1-a=0.90, n=30
10. Given a standardized normal distribution (with a mean of 0 and a standard deviation of 1), complete parts (a) through (d). a. What is the probability that Z is less than 1.01? b. What is the probability that Z is greater than -0.27? c. What is the probability that Z is less than -0.27 or greater than the mean? d. What is the probability that Z is less the -0.27 or greater than 1.01? 11. Which of the following events occur with a probability of zero? a. A person who is both male and female b. An individual who runs quickly and swims slowly c. A product that is neither foreign nor domestic d. A math problem that is neither arithmetic nor geometry 12. Suppose you read a website that says that an international health organization found that 15 % of children in a certain country have pneumonia. On what type of data source is the claim in this story based? A. These data are result of an observational study. B. These data are distributed by organization. C. These data are outcomes of a designed experiment. D. These data are collected by ongoing business activities. E. These data are responses from a survey. 13. Consider a population of 1024 mutual funds that primarily invest in large companies. You have determined that μ , the mean one-year total percentage return achieved by all the funds, is 5.80 and that σ , the standard deviation, is 1.25. a. According to the empirical rule, what % of these funds is expected to be within + 3 standard deviations of the mean? b. According to the Chebyshev rule, what % of these funds are expected to be within + 4 standard deviations of the mean? c. According to the Chebyshev rule, at least 88.89% of these funds are expected to have one-year total returns between what two amounts? 14. Fitting a straight line to a set of data yields the following prediction line. Complete (a) through (c) below. Yi =17−0.4X i a. Interpret the meaning of the Y-intercept, b 0 . b. Interpret the meaning of the slope, b 1 .

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