USING EXCEL step by step

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1. (15 points) An important issue facing Americans is the large number of medical malpractice lawsuits and the expenses that they generate. In a study of 1223 randomly selected medical malpractice lawsuits, it is found that 856 of them were later dropped or dismissed (based on data from the Physician Insurers Associa- tion of America). (a) What is the best point estimate of the proportion of medical malpractice law- suits that are dropped or dismissed? (b) Construct a 99% confidence interval estimate of the proportion of medical malpractice lawsuits that are dropped or dismissed. (c) Does it appear that the majority of such suits are dropped or dismissed? 2. (15 points) How many adults must be randomly selected to estimate the mean FICO (credit rating) score of working adults in the United States. We want 95% confidence that the sample mean is within 3 points of the population mean, and the population standard deviation is 68. 3. (20 points) (a) The listed values are waiting times (in minutes} of customers at the Jet- ferson Valley Bank, where customers enter a single waiting line that feeds three teller windows. Construct a 95% condence interval for the population standard deviation 0. - J 6.5 6.6 6.7 6.6 7.1 7.3 7.4 7.7 7.7 7.7 (b) When customers may)r enter anyr one of three different lines that have formed at three teller windows we obtain the following waiting times. Construct a 95% confidence interval for the population standard deviation 0'. l4.2|5.4 5.8 6.2 6.7 7.7 7.7 8.5 9.3 10.0| (c) Interpret the results found in parts (a) and (b). Do the confidence intervals suggest a difference in the variation among waiting times? 4. (15 points} In 280 trials with professional touch therapists, correct responses to a question were obtained 123 times. Test the claim that p > 0.5 (the proportion of correct responses is greater than the proportion of 0.5 that would be expected with random chance). What is the value of the sample proportion? Based on the P-value, what should we conclude about the claim that p > 0.5? 5. (15 points) Listed below are birth weights (in kilograms) of male babies born to mothers on a special vitamin supplement (based on data from the New York State Department of Health). Test the claim that this sample comes from a population with a standard deviation equal to 0.470 kg, which is the standard deviation for male birth weights in general. Use a 0.05 significance level. Does the vitamin supplement appear to affect the variation among birth weights? 3.73|4.37 3.73 4.33 3.39 3.66 4.68 3.52 3.02 4.09 2.47 4.13 4.47 3.22 3.43 2.54 6. (20 points) Below we have information about a simple random sample of Hitachi televisions. We have recorded their price (in dollars) and their quality scores. Price 2300 1300 2500 2200 2000 1700 1500 2400 Qualityscorel 74 | 67 7o 66 63 | 62 52 68 | (a) What is the sample correlation between Hitachi television prices and their quality scores. (b) Does the plot of these variables confirm that there is a linear correlation? (c) Is this correlation significant? (d) Find the best predicted qualityr score of a Hitachi television with a price of $1900