Exam 26: Understanding Probability Distributions and Statistical Inference

Use the following to answer the question(s) below. A newspaper poll asked respondents if they trusted "eco friendly" labels on cleaning products. Out of 1000 adults surveyed, 498 responded "yes." We would like to test if the proportion of respondents that trust these labels is at least 50%. -The correct alternative hypothesis is

Suppose that 6 economists who work for the federal government and 7 university economists were asked to grade the effectiveness of an economic stimulus bill in terms of its ability to increase jobs over the next two years. What nonparametric method is appropriate for testing if the two groups differ in terms of their opinion?

Which of the following is not an assumption or condition that needs to be checked for a paired t-interval?

Use the following to answer the question(s) below. Three brands of AAA batteries are compared to determine if differences in lifetime exist. Each brand is tested in four devices (TV remote, hand-held game, flashlight and digital camera). The experiment is run once for each combination of brand and device. The twelve runs are ordered randomly. The time (in minutes) that each battery lasts under continuous usage is recorded. The partial ANOVA results are as follows: -The F-statistic for testing whether the three brands of AAA batteries have equal mean lifetimes is

Use the following to answer the question(s) below. Preparing wheat for use in bread and pasta products generally involves both milling and bleaching. A company that processes wheat is interested in determining the best combination of milling and bleaching that results in a desirable wheat product without sacrificing fibre content. They vary the milling time (short, medium and long) and bleaching (no bleaching and bleaching) and measure fibre content (gms/100 grams) of the resulting wheat product. The partial ANOVA results apply. -The F-statistic for testing whether milling has an effect on fibre content is

A contact lens wearer read that the producer of a new contact lens boasts that their lenses are cheaper than contact lenses from another popular company. The null hypothesis H0: μold - μnew = 0 is tested against the alternative HA: μold - μnew > 0. Which of the following would be a Type II error?

A professor was interested in determining whether the prices of new textbooks in the bookstore were higher than if purchased online. She selected 6 textbooks and priced each at the bookstore and online. Which statement is true at 5% significance level?

Suppose that ten new smart phone models were evaluated by two consumer electronics magazines (Popular Electronics and Electronics Now) from 1 (best) to 10 (worst) as shown below. Why is the Spearman's rho more appropriate than the correlation coefficient for these data?

Use the following to answer the question(s) below. IT staff for a large corporation has developed the following probability distribution for the number of calls requiring troubleshooting problems per day. -The standard deviation of the sampling distribution of mean times is

Use the following to answer the question(s) below. A local politician was interested in determining whether income level affects opinion regarding the governments' bailout bill of the auto industry during the 2008 financial crisis. He surveyed a sample of his constituents and got the following results. Opinion -The correct null hypothesis to be tested is

Suppose that ten new smart phone models were evaluated by two consumer electronics magazines (Popular Electronics and Electronics Now) from 1 (best) to 10 (worst) as shown below. To determine if there is a difference in the rankings between the two magazines, the appropriate nonparametric method is

A P-value indicates

The best tasting ice creams are generally high in fat content, which gives them a creamy texture. Four brands of ice cream were tested by consumers who graded their level of creaminess (A = very creamy to F = not creamy). Each brand was rated by a different group of consumers (the data are shown below). Using the Kruskal-Wallis test, the value of H is

Use the following to answer the question(s) below. The weights of soy patties sold by Veggie Burgers Delight are normally distributed. A random sample of 15 patties yields a mean weight of 108 grams with a sample standard deviation of 14 grams. At the 0.05 level of significance, perform a hypothesis test to see if the true mean weight is less than 113 grams. -The correct null and alternative hypotheses are

An urban planning group is interested in estimating the difference in mean household income between two neighbourhoods. They obtain the following 95% confidence interval: (-5693, -4107) Which of the following is true?

Use the following to answer the question(s) below. IT staff for a large corporation has developed the following probability distribution for the number of calls requiring troubleshooting problems per day. -Which is true about a 99% confidence interval based on a given sample?

Use the following to answer the question(s) below. Chris Columbus is responsible for controlling inventory levels for four types of sailboats sold by his company. Chris takes a sample of 48 boats sold over the past several months to determine if demand is the same for each type. His results are as follows: -The correct null hypothesis to be tested is

Use the following to answer the question(s) below. IT staff for a large corporation has developed the following probability distribution for the number of calls requiring troubleshooting problems per day. -The standard deviation of the number of calls per day is

Use the following to answer the question(s) below. A sample of 30-year fixed mortgage rates at 12 randomly chosen credit unions yields a mean rate of 6.65 % and a sample standard deviation of 0.39%. A sample of 30-year fixed mortgage rates at 16 randomly selected banks yields a mean rate of 7.05% and a sample standard deviation of 0.22%. Are the mean rates different between credit unions and banks? Relevant output is shown below. -Which of the following is true?

Use the following to answer the question(s) below. Preparing wheat for use in bread and pasta products generally involves both milling and bleaching. A company that processes wheat is interested in determining the best combination of milling and bleaching that results in a desirable wheat product without sacrificing fibre content. They vary the milling time (short, medium and long) and bleaching (no bleaching and bleaching) and measure fibre content (gms/100 grams) of the resulting wheat product. The partial ANOVA results apply. -The F-statistic for testing whether bleaching has an effect on fibre content is