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Hypothesis testing comparing two populations, confidence intervals, comparisons multiple proportions

1- excel sheet with all calculations

2- word document with interpretation of the results (ex. explain results of the test mean in the context of the problem.

Data given is contains insurance classification, price and attributes of some cars in 1987. The aim of the study is to understand how insurance risk ratings and car attributes affect the price at which a car is sold. The variables in the data set are as follows:

 1. Risk rating -3, -2, -1, 0, 1, 2, 3. 2. Risk factor Risky, neutral, safe 3. make alfa-romero, audi, bmw, chevrolet, dodge, honda, isuzu, jaguar, mazda, mercedes-benz, mercury, mitsubishi, nissan, peugot, plymouth, porsche, renault, saab, subaru, toyota, volkswagen, volvo 4. fuel-type diesel, gas. 5. aspiration standard, turbo. 6. num-of-doors four, two. 7. body-style hardtop, wagon, sedan, hatchback, convertible. 8. drive-wheels 4wheel drive (4wd), forward wheel drive (fwd), rear wheel drive (rwd). 9. engine-location front, rear. 10. wheel-base continuous from 86.6 120.9. 11. length continuous from 141.1 to 208.1. 12. width continuous from 60.3 to 72.3. 13. height continuous from 47.8 to 59.8. 14. curb-weight continuous from 1488 to 4066. 15. engine-type dohc, dohcv, l, ohc, ohcf, ohcv, rotor. 16. num-of-cylinders eight, five, four, six, three, twelve, two. 17. engine-size continuous from 61 to 326. 18. fuel-system 1bbl, 2bbl, 4bbl, idi, mfi, mpfi, spdi, spfi. 19. bore continuous from 2.54 to 3.94. 20. stroke continuous from 2.07 to 4.17. 21. compression-ratio continuous from 7 to 23. 22. horsepower continuous from 48 to 288. 23. peak-rpm continuous from 4150 to 6600. 24. city-mpg continuous from 13 to 49. 25. highway-mpg continuous from 16 to 54. 26. price continuous from 5118 to 45400.

We would like to understand how the variables interact with each other. Write a report that includes the following:

1. Calculate and interpret 95% confidence intervals of the proportion of cars that have four doors
2. Auto world magazine published an article on car efficiency in Dec 1987. The article claimed that the average highway mileage of cars in 1987 was higher than that in 1985. Test auto worldâ€™s hypothesis assuming that the average highway mileage in 1985 was 26 mpg.
3. Test the hypothesis that on average neutral-risk cars are more expensive than risky cars.
4. Test for the independence of the risk factor and wheel drive (fwd, rwd and 4wd).