Exam 13: Inference for Counts: Chi-Square Tests

A real estate agency, located in a metropolitan area in the northeastern U.S., kept data on the various types of properties purchased in the area. Historically, 15% of Purchases were for condominiums, 30% were for townhouses, 40% for single family Homes, 10% for commercial properties and 5% for land. With changing demographics, The agency wondered if the current distribution matches the historical distribution. Recent data showed the following: Type of Property Condos Townhouses Homes Commercial Land Frequency 89 121 78 25 12 Which Chi-square test is most appropriate for this situation?

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

By examining residuals, determine which type of property had the most impact on the test results? What are the implications for the real estate agency?

An online department store wants to determine if there is an association between coupon redemption and gender. After a special coupon broadcast to its reward members, The following data on coupon redemption at check out were collected. The correct value Of the test statistic is Coupon Redeemed?

Data were collected on annual personal time (in hours) taken by a random sample of 16 women and 7 men employed by a medium sized company. The women took an Average of 24.75 hours of personal time per year with a standard deviation of 2.84 hours. The men took an average of 21.89 hours of personal time per year with a standard Deviation of 3.29 hours. The Human Resources Department believes that women tend to Take more personal time than men because they tend to be the primary child care givers in The family. The t-test for two means is appropriate in this situation because

A manufacturing plant for recreational vehicles receives shipments from three different parts vendors. There has been a defect issue with some of the electrical wiring in the Recreational vehicles manufactured at the plant. The plant manager believes that the Defect issue is dependent on the parts vendor. The plant manager reviews a sample of Quality assurance inspections from the last six months. The expected number of perfect Parts from Made-4-U Co. is

A real estate agency, located in a metropolitan area in the northeastern U.S., kept data on the various types of properties purchased in the area. Historically, 15% of purchases Were for condominiums, 30% were for townhouses, 40% for single family homes, 10% For commercial properties and 5% for land. With changing demographics, the agency Wondered if the current distribution matches the historical distribution. Recent data Showed the following: Type of Property Condos Townhouses Homes Commercial Land Frequency 89 121 78 25 12 The value of the Chi-square test statistic is

We have created a 95% confidence interval for µ with the result (10, 15). What $\text { conclusion will we make if we test } \mathrm { H } _ { 0 } : \mu = 16 \text { versus } \mathrm { H } _ { A } : \mu \neq 16 \text { at } \alpha = 0.05 ?$

A manufacturing plant for recreational vehicles receives shipments from three different parts vendors. There has been a defect issue with some of the electrical wiring in The recreational vehicles manufactured at the plant. The plant manager believes that the Defect issue is dependent on the parts vendor. The plant manager reviews a sample of Quality assurance inspections from the last six months. The P-value of the calculated Chi- Square statistic is 0.1161. At α = 0.05, we should

Suppose that a manufacturer is testing one of its machines to make sure that the machine is producing more than 97% good parts()H₀A: pp=>0.97 and H : 0.97 . The test results in a P-value of 0.102. In reality, the machine is producing 99% good Parts. What probably happens as a result of our testing?

A real estate agency, located in a metropolitan area in the northeastern U.S., kept data on the various types of properties purchased in the area. Historically, 15% of purchases Were for condominiums, 30% were for townhouses, 40% for single family homes, 10% For commercial properties and 5% for land. With changing demographics, the agency Wondered if the current distribution matches the historical distribution. Recent data Showed the following: Type of Property Condos Townhouses Homes Commercial Land Frequency 89 121 78 25 12 Which Chi-square test is most appropriate for this situation?

A P-value indicates

The weights of soy patties sold by Veggie Burgers Delight are normally distributed. A random sample of 15 patties yields a mean weight of 3.8 ounces with a sample standard Deviation of 0.5 ounces. At the .05 level of significance, perform a hypothesis test to see If the true mean weight is less than 4 ounces. The correct calculated value of the test statistic is

Before being released to market, a drug company tests a new allergy medication for potential side effects. A random sample of 160 individuals with allergies was selected for The study. The new allergy medication was randomly assigned to 80 of them, and another Popular allergy medication already on the market (Brand C) was assigned to the rest. Out Of the 80 given the new allergy medication, 14 reported drowsiness; 22 of the 80 taking Brand C reported drowsiness. The 95% confidence interval for the difference in Proportions reporting drowsiness is -0.028 to 0.228. Which of the following is correct?

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: Type of Boat Sales Pirate's Revenge 15 Jolly Roger 11 Sails Delight 10 Cruiser Cove 12 At the 0.05 level of significance, the correct conclusion is

The weights of soy patties sold by Veggie Burgers Delight are normally distributed. A random sample of 15 patties yields a mean weight of 3.8 ounces with a sample standard Deviation of 0.5 ounces. At the 0.05 level of significance, perform a hypothesis test to See if the true mean weight is less than 4 ounces. The correct null and alternative hypotheses are

A real estate agency, located in a metropolitan area in the northeastern U.S., kept data on the various types of properties purchased in the area. Historically, 15% of purchases Were for condominiums, 30% were for townhouses, 40% for single family homes, 10% For commercial properties and 5% for land. With changing demographics, the agency Wondered if the current distribution matches the historical distribution. Recent data Showed the following: Type of Property Condos Townhouses Homes Commercial Land Frequency 89 121 78 25 12 The value of the Chi-square test statistic is

Vending machines on a college campus offer a variety of snacks. The purchasing agent believes that each type of snack is equally preferred by students and consequently Orders equal quantities. The number of snacks sold from vending machines on this Campus for the last six months is shown in the following table. If the purchasing agent is Correct, how many candy bars would we expect to have been sold? Snack Type Chips Candy Bars Crackers Nuts Purchase Frequency 159 198 174 149

Absorption rates into the body are important considerations 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 $\mathrm { H } _ { 0 } : \mu _ { G } - \mu _ { B } = 0$ against the Alternative $\mathrm { H } _ { A } : \mu _ { G } - \mu _ { B } \neq 0$ Which of the following would be a Type I error?

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