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Automobiles Purchased An automobile owner found that 20years ago, 72% of Americans said that they would prefer to purchase an American automobile. He believes that the number differs from72% today. He selected a random sample of 43 Americans and found that 38 said that they would prefer an American automobile. Can it be concluded that the percentage today differs from 72% ? At a-0.10 is he correct? Use the critical value method with tables.
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Use u1 for the mean out-of-state tuition of private colleges. The 95confidence interval for the difference of the means is <u1-u2<
Bartelby Ages of Homes Whiting, Indiana leads thee "Top 100 Cities with the Oldest Houses" list with the average age of houses being 66.4 years. Farther down the list resides Franklin, Pennsylvania, with an average house age of 59.4 years. Researchers selected a random sample of 22 houses from Whiting and 19 houses from Franklin and obtained the following statistics. At α=0.05, can it be concluded that the houses in Whiting are older? Use the P-value method. Assume the variables are
Use μ1 for the average age of houses in Whiting. (a) State the hypotheses and identify the claim.
(b) Compute the test value. Round the answer to at least three decimal places. t= (c) Find the interval for the P-value. The correct interval is (d) Make the decision. Reject/do not reject the null hypothesis. (e) Summarize the results. There is/is not enough evidence to support the claim that the houses in Whiting are older. Age of Senators The average age of senators in the108th Congress was 59 years. If the standard deviation was 12.5 years, find the z -scores corresponding to the oldest and youngest senators of age 88 and 46 . Round z scores to two decimal places.
PGA Golf Scores At a recent PGA tournament (the Honda Classic at Palm Beach Gardens, Florida) the following scores were posted for eleven randomly selected golfers for two consecutive days. At α=0.20, is there evidence of a difference in mean scores for the two days? Assume the variables are normally or approximately normally distributed and use μD for the mean on Thursday minus the mean on Friday. Golfer 1 2 3 4 5 6 7 8 9 10 11 Thursday 69 70 68 70 68 68 65 67 65 64 66 Friday 75 67 74 70 67 68 70 69 71 72 69 (a) State the hypotheses. H0: claim/do not claim? H1: claim/do not claim? This hypothesis test is one tailed/two tailed? (b) Find the critical value. Enter the answers in ascending order and rounded to at least three decimal places. Critical value= Compute the test value. Round score values to at least three decimals places. t= Make the decision. Reject/Do not reject the null hypothesis (e) Summarize the results.
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- In a city with three high schools, all the ninth graders took a Standardized Test, with these results: Number of ninth graders High School Mean score on test Glenwood 77 264 Central City Lincoln High 91 303 70 170 The city's PR manager, who never took statistics, claimed the mean score of all ninth graders in the city was 79.3. Of course, that is incorrect. What is the mean score for all ninth graders in the city? Round to one decimal place. mean of all ninth grader's scores =arrow_forwardI am lookin for the relationship between the sample mean and the population mean and also the relationship between the standard error and the sample size.arrow_forwardSuppose you are interested in testing whether the mean earning of men in California differs significantly from the mean earning of men in New York. If the number of men from California in the sample is 123 and the number of men from New York in the sample is 88, how many degrees of freedom are there?arrow_forward
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