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Concept explainers
(c) Find (or estimate) the P-value. Sketch the sampling distribution and show the area corresponding to the P-value.
(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level
(e) Interpret your conclusion in the context of the application.
Note: For degrees of freedom d.f. not given in the Student's t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the p-value by a small amount and therefore produce a slightly more “conservative" answer.
Meteorology: Storms Weatherwise is a magazine published by the American Meteorological Society. One issue gives a rating system used to classify Nor'easter storms that frequently hit New England and can cause much damage near the ocean. A severe storm has an average peak wave height of
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Chapter 9 Solutions
Understanding Basic Statistics
- Suppose that a class’s test scores have a mean of 80 and standard deviation of 5. You choose 25 students from the class. What’s the chance that the group’s average test score is more than 82?arrow_forwardSuppose that you collect data on 10 products and check their weights. The average should be 10 ounces, but your sample mean is 9 ounces with standard deviation 2 ounces. Find the standard score.What percentile is the standard score found in part a of this question closest to?Suppose that the mean really is 10 ounces. Do you find these results unusual? Use probabilities to explain.arrow_forwardSuppose that you want to sample expensive computer chips, but you can have only n=3 of them. Should you continue the experiment?arrow_forward
- Suppose that studies claim that 40 percent of cellphone owners use their phones in the car while driving. What’s the chance that more than 425 out of a random sample of 1,000 cellphone owners say they use their phones while driving?arrow_forwardSuppose that the average length of stay in Europe for American tourists is 17 days, with standard deviation 4.5. You choose a random sample of 16 American tourists. The sample of 16 stay an average of 18.5 days or more. What’s the chance of that happening?arrow_forwardHow do you recognize that a statistical problem requires you to use the CLT? Think of one or two clues you can look for. (Assume quantitative data.)arrow_forward
- Suppose that you take a sample of 100 from a skewed population with mean 50 and standard deviation 15. What sample size condition do you need to check here (if any)?What’s the shape and center of the sampling distribution for ?What’s the standard error?arrow_forwardQuestion 3 The following stem-and-leaf displays the weekly salary of employees at this firm. Stem-and-Leaf Display Leaf Unit = 10.0 N=x 5 3 00123 12 4 0125888 (y) 5 11234456777 z 6 13568 5 7 154 2 8 46 i. Determine the value of x, y and z. [3] ii. What is the value of the median? [2] iii. Find the mode of this data set. iv. Calculate the range [1] [2]arrow_forwardLet Y be a continuous RV with PDF otherwise Find the CDF, Fry), of Y . Find an expression for pth, p € (0, 1), quantile of the distribution. Find E(Y) and V(Y). Find E(-2Y + 1) and V(-3Y - 2). Find E(Y3).arrow_forward
- Let X be a continuous RV with CDF Find P(X < 0), P(-1 < X < 1) and P(0.5 < X). Based on your answers to the above questions, what is the median of the distribu-tion? Why Find the PDF, fx (x), of X.arrow_forwardA survey of 581 citizens found that 313 of them favor a new bill introduced by the city. We want to find a 95% confidence interval for the true proportion of the population who favor the bill. What is the lower limit of the interval? Enter the result as a decimal rounded to 3 decimal digits. Your Answer:arrow_forwardLet X be a continuous RV with PDF where a > 0 and 0 > 0 are parameters. verify that f-∞ /x (x)dx = 1. Find the CDF, Fx (7), of X.arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill
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