Exam 26: Understanding Probability Distributions and Statistical Inference

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: -Which of the following statements is true about this design?

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%. -At the 0.01 level of significance, the correct conclusion is

Use the following to answer the question(s) below. Insurance company records indicate that 10% of its policyholders file claims involving theft or robbery of personal property from their homes. Suppose a random sample of 400 policyholders is selected. -The standard deviation of the sampling distribution of the sample proportion of policyholders filing claims involving theft or robbery of personal property from their homes is

Use the following to answer the question(s) below. A government agency has 6000 employees. As an alternative to the traditional five day work week, employees were asked whether they preferred a four-day work week (10 hours per day) or flexible hours. The table below shows the results by age category. -What is the probability that an employee at this government agency prefers a four-day work week?

Based on the scatterplot shown below, what makes a nonparametric method more appropriate than the Pearson correlation for measuring the association between the two variables?

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 calculated value of the Chi-square statistic is

Use the following to answer the question(s) below. A government agency has 6000 employees. As an alternative to the traditional five day work week, employees were asked whether they preferred a four-day work week (10 hours per day) or flexible hours. The table below shows the results by age category. -What is the probability that an employee prefers flex hours given that he/she is in the 30-45 age group?

Use the following to answer the question(s) below. In economic downturns companies attempt to downsize their workforces by offering early retirement incentives to older employees. A survey of 723 companies found that 195 engage in such downsizing practices. -The estimated proportion of companies that downsize their workforces by offering early retirement incentives is

We have created a 95% confidence interval for the true proportion with the result (0.10, 0.15). What conclusion will we make if we test H0: p = 0.16 versus HA: p ≠ 0.16 at α = 0.05?

Use the following to answer the question(s) below. A publishing company conducted a survey of its readership and found that 60% subscribed to Food & Wine, 30% subscribed to Wine Spectator, and 25% subscribed to both. -The probability that a reader subscribes to Food & Wine or Wine Spectator is

Use the following to answer the question(s) below. A survey of investors finds that 60% use a full service brokerage firm to invest in stocks, 30% trade stocks online and 24% do both. -The probability that an investor selected at random uses a full service brokerage firm to invest in stocks or trades stocks online 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. -After computing a confidence interval, the investigator believes that the results are meaningless because the width of the interval is too large. In reconstructing the interval, the investigator should

A telecommunications company is interested in determining the likelihood of a new breakthrough technology being developed in the next ten years. What type of probability would they use to estimate the likelihood?

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 value of the test statistic 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. The grades are shown in below. Using the appropriate nonparametric method, the calculated value of the test statistic is

Absorption rates into the body are important factors when manufacturing a generic version of a brand-name drug. A pharmacist read that the absorption rate into the body of a new generic drug (G) is the same as its brand-name counterpart (B). She has a researcher friend of hers run a small experiment to test H0: μG - μB = 0 against the alternative HA: μG - μB ≠ 0. Which of the following would be a Type I error?

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. -Which of the following is true about this study?

A truck company wants on-time delivery for at least 98% of the parts they order from a metal manufacturing plant. They have been ordering from Hudson Manufacturing but will switch to a new, cheaper manufacturer (Steel-R-Us) unless there is evidence that this new manufacturer cannot meet the 98% on-time goal. As a test the truck company purchases a random sample of metal parts from Steel-R-Us, and then determines if these parts were delivered on-time. Which hypotheses should they test?

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. -If a population is normally distributed with µ = 500 and σ = 50, and a sample of size 20 is selected, the probability that the sample mean falls between 450 and 550 will be ________ the probability that an individual value falls between 450 and 550.

Use the following to answer the question(s) below. A manufacturer of cordless electric shavers sampled 13 from a day's production and found the mean time of continuous usage without recharging to be 410 minutes with a sample standard deviation of 30 minutes. We can assume that times are normally distributed. We wish to test if the true mean operating time without recharging is more than 400 minutes. -The correct conclusion at the 0.05 level of significance is