[8 marks] It is said that drinking cranberry juice can help prevent urinary tract infections in

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[8 marks] It is said that drinking cranberry juice can help prevent urinary tract infections in women. In a laboratory study, female subjects prone to these infections were monitored over a year, while regularly drinking certain beverages. The contingency table shows the relationship between the three different types of beverage and incidence of urinary tract infections in the subjects. Cranberry Juice Lactobacillus Neither(Control) Infection 8 24 9 No infection 42 36 16 (a) Perform a chi-squared hypothesis test at the 5% significance level to evaluate the evidence of an association between type of beverage and incidence of urinary tract infections based on this data. Be sure to discuss the relevant statistical assumptions. [6] (b)…show more content…
The data is in the file TyreWear.csv. (a) Use an appropriate t-test on the data using Excel (α = 0.01) to determine if there is any difference in mean tread wear using the two methods. Write a report on this hypothesis test, stating appropriate hypotheses clearly, the decision rule used, necessary assumptions and concise conclusions. [6] (b) Do you expect a 99% confidence interval for the average difference in tread wear for these methods to contain zero? Why? [1] 4. [6 marks] A survey in 2008 undertaken by the Royal Automobile Club investigated the concerns of commuters using Perth public transport services. The main concerns were overcrowding, personal safety, poor connections, that the service was not frequent enough, and the unreliability of the service. (Source: Accessed 1/4/2011 from http://rac.com.au/about-us/community/campaigns/public-transport.aspx ) From the survey, the most cited reason for using public transport was for work purposes (56%), followed by other essential services (20%), education (8%) and shopping (6%), with other reasons given by the remaining survey respondents. A similar survey of 418 people was conducted recently on the reasons for using public transport with the following results: Work purposes Education Shopping Essential Services Other 252 51 24 71 20 Use an appropriate statistical test at a 1% significance level to determine if the observed distribution of

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