that tires are replaced after six years of age. But a survey showed that many car owners ignore that advice and wait longer to replace the tires on their vehicles. The following data show the age, in years, for 10 vehicles whose tires were recently brought in to the dealer for a tire replacement. 11.2 9.7 10.1 10.0 10.9 7.7 9.9-10.3 10.1 10.6 Based on this sample, compute the descriptive statistics (in years) in parts (a) and (b) and then answer the questions in parts (c) and (d). (a) mean, median, and mode (in years) mean years years years median mode (b) range and standard deviation (in years) (Round your answers to four decimal places.) range years years standard deviation (c) Compute the z-score for a set of tires with an age of 7.7 years. (Round your answer to four decimal places.) z = Should the age of 7.7 years be considered an outlier in comparison to the other tire ages? The age of 7.7 years is-Select-than three standard deviations away from the mean age, therefore it -Select- be considered an outlier. (d) Do the ages indicate that car owners are complying with carmaker recommendations? Should the carmakers consider making changes to their recommendations? Would offering incentives to car owners to replace tires earlier be a possible solution? The carmaker recommendation of replacing used tires after six years --Select- being met. The carmakers -Select- consider making changes to their recommendations and -Select- consider offering incentives to replace tires earlier.

Researchers wished to know if they could conclude that two populations of infants differ with respect to mean age at which they walked alone. The following data (ages in months) were collected: Sample from population A: Sample from population B: 9.5, 10.5, 9.0, 9.75, 10.0, 13.0, 10.0, 13.5, 10.0, 9.5, 10.0, 9.75 12.5, 9.5, 13.5, 13.75, 12.0, 13.75, 12.5, 9.5, 12.0, 13.5, 12.0, 12.0 What should the researchers conclude? Let a = .05.

You may need to use the appropriate appendix table or technology to answer this question. The increasing annual cost (including tuition, room, board, books, and fees) to attend college has been widely discussed (Time.com). The following random samples show the annual cost of attending private and public colleges. Data are in thousands of dollars. Private Colleges Public Colleges 52.8 44.2 45.0 33.3 44.0 20.3 22.0 28.2 15.6 24.1 28.5 31.6 44.8 36.8 50.5 43.0 22.8 25.8 18.5 25.6 14.4 21.8 (a) Compute the sample mean (in thousand dollars) and sample standard deviation (in thousand dollars) for private colleges. (Round the standard deviation to two decimal places.) sample mean $ 42.6 v thousand sample standard deviation $ 6.85 v thousand Compute the sample mean (in thousand dollars) and sample standard deviation (in thousand dollars) for public colleges. (Round the standard deviation to two decimal places.) v thousand v thousand sample mean $ 22.3 sample standard deviation $ 4.53 (b) What…

Use the following data to determine if there is a significant difference between children at different school levels on how many hours per day, they actually wear their orthodontic appliances. Evaluate using a two-tailed test with . Primary School Junior High School High School 16 9 20 14 13 15 18 14 16   12 18