Performing a Chi-Square Goodness-of-Fit Test In Exercises 7−16, (a) identify the claim and state H0 and Ha, (h) find the critical value and identify the rejection region, (c) find the chi-square test statistic, (d) decide whether to reject or fail to reject the null hypothesis, and (e) interpret the decision in the context of the original claim.
15. Home Sues An organization claims that the number of prospective home buyers who want their next house to be larger, smaller, or the same size as their current house is not uniformly distributed. To test this claim, you randomly select 800 prospective home buyers and ask them what size they want their next house to be. The table at the left shows the results. At α = 0.05, test the organization's claim. (Adapted from Better Homes and Gardens)
Response | Frequency, f |
Urger | 285 |
Same size | 224 |
Smaller | 291 |
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Elementary Statistics: Picturing the World (7th Edition)
- Population Genetics In the study of population genetics, an important measure of inbreeding is the proportion of homozygous genotypesthat is, instances in which the two alleles carried at a particular site on an individuals chromosomes are both the same. For population in which blood-related individual mate, them is a higher than expected frequency of homozygous individuals. Examples of such populations include endangered or rare species, selectively bred breeds, and isolated populations. in general. the frequency of homozygous children from mating of blood-related parents is greater than that for children from unrelated parents Measured over a large number of generations, the proportion of heterozygous genotypesthat is, nonhomozygous genotypeschanges by a constant factor 1 from generation to generation. The factor 1 is a number between 0 and 1. If 1=0.75, for example then the proportion of heterozygous individuals in the population decreases by 25 in each generation In this case, after 10 generations, the proportion of heterozygous individuals in the population decreases by 94.37, since 0.7510=0.0563, or 5.63. In other words, 94.37 of the population is homozygous. For specific types of matings, the proportion of heterozygous genotypes can be related to that of previous generations and is found from an equation. For mating between siblings 1 can be determined as the largest value of for which 2=12+14. This equation comes from carefully accounting for the genotypes for the present generation the 2 term in terms of those previous two generations represented by for the parents generation and by the constant term of the grandparents generation. a Find both solutions to the quadratic equation above and identify which is 1 use a horizontal span of 1 to 1 in this exercise and the following exercise. b After 5 generations, what proportion of the population will be homozygous? c After 20 generations, what proportion of the population will be homozygous?arrow_forwardConduct a t-test at the .01 level. Find the correct decision about the null hypothesis. (A) Because the t-statistic exceeds the critical values, we fail to reject the null hypothesis. (B) Because the t-statistic exceeds the critical values, we reject the null hypothesis. (C) Because the t-statistic does not exceed the critical values, we fail to reject the null hypothesis. (D) Because the t-statistic does not exceed the critical values, we reject the null hypothesis.arrow_forwardFinding Critical Values and Confidence Intervals. In Exercises 5–8, use the given information to find the number of degrees of freedom, the critical values χ2L and X2R, and the confidence interval estimate of σ. The samples are from Appendix B and it is reasonable to assume that a simple random sample has been selected from a population with a normal distribution. Nicotine in Menthol Cigarettes 95% confidence; n = 25, s = 0.24 mg White Blood Cell Counts of Men 95% confidence; n = 153, s = 1.86. Platelet Counts of Women 99% confidence; n = 147, s = 65.4. Heights of Men 99% confidence; n = 153, s = 7.10 cmarrow_forward
- Testing Claims About Variation. In Exercises 5–16, test the given claim. Identify the null hypothesis, alternative hypothesis, test statistic, P-value, or critical value(s), then state the conclusion about the null hypothesis, as well as the final conclusion that addresses the original claim. Assume that a simple random sample is selected from a normally distributed population. Fast Food Drive-Through Service Times Listed below are drive-through service times (seconds) recorded at McDonald’s during dinner times (from Data Set 25 “Fast Food” in Appendix B). Assuming that dinner service times at Wendy’s have standard deviation σ = 55.93 sec, use a 0.01 significance level to test the claim that service times at McDonald’s have the same variation as service times at Wendy’s. Should McDonald’s take any action?arrow_forwardLarge Data Sets from Appendix B. In Exercises 17 and 18, use the data set from Appendix B to test the given claim. Identify the null hypothesis, alternative hypothesis, test statistic, P-value, or critical value(s), then state the conclusion about the null hypothesis, as well as the final conclusion that addresses the original claim. Fast Food Drive-Through Service Times Repeat Exercise 15 using the 50 service times for McDonald’s during dinner times in Data Set 25 “Fast Food.”arrow_forwardA nutrition study investigated knowledge about fruit juices. The study was conducted in a pediatric clinic. Accompanying parents were asked to classify a national brand of “fruit drink”, that contains less than 10% fruit juice, as 100% fruit juice, fruit juice mix, or no fruit juice at all. The investigators asked 150 parents. The table contains the results. Juice Content Gender Female Gender Male Total 100% 15 15 30 1%-99% 55 25 80 0% 30 10 40 100 50 150 The chi‑square statistic for the null hypothesis of independence has: - 6 degrees of freedom. - 3 degrees of freedom. - 2 degrees of freedom. - 4 degrees of freedom.arrow_forward
- (b) Find the critical value(s) and identify the rejection region(s). (c) Calculate d and sd. (d) Find the standardized test statistic t. (e) Decide whether to reject or fail to reject the null hypothesis and interpret the decision in the context of the original claim.arrow_forward(b) Find the critical value(s) and identify the rejection region(s). (c) Calculate d and sd. (d) Find the standardized test statistic t. (e) Decide whether to reject or fail to reject the null hypothesis and interpret the decision in the context of the original claim.arrow_forwardTesting Claims About Proportions. In Exercises 7–22, test the given claim. Identify the null hypothesis, alternative hypothesis, test statistic, P-value or critical value(s), then state the conclusion about the null hypothesis, as well as the final conclusion that addresses the original claim. Does Aspirin Prevent Heart Disease? In a trial designed to test the effectiveness of aspirin in preventing heart disease, 11,037 male physicians were treated with aspirin and 11,034 male physicians were given placebos. Among the subjects in the aspirin treatment group, 139 experienced myocardial infarctions (heart attacks). Among the subjects given placebos, 239 experienced myocardial infarctions (based on data from “Final Report on the Aspirin Component of the Ongoing Physicians’ Health Study,” New England Journal of Medicine , Vol. 321: 129–135). Use a 0.05 significance level to test the claim that aspirin has no effect on myocardial infarctions. a. Test the claim using a hypothesis test. b.…arrow_forward
- Which bit of information is not obtainable from the results of a t-test written up in a statistical report? a. the alpha level used in the hypothesis test b. the degrees of freedom used in the hypothesis test c. whether the null hypothesis is rejected or fails to be rejected d. Each of these bits of information is obtainable from the results of a t-test written up in a statistical report.arrow_forwardLarge Data Sets from Appendix B. In Exercises 17 and 18, use the data set from Appendix B to test the given claim. Identify the null hypothesis, alternative hypothesis, test statistic, P-value, or critical value(s), then state the conclusion about the null hypothesis, as well as the final conclusion that addresses the original claim. Mint Specs Repeat Exercise 16 using the weights of the 37 post-1983 pennies included in Data Set 29 “Coin Weights” in Appendix B.arrow_forwardtest the given claim. Identify the null hypothesis, alternative hypothesis, test statistic, P-value or critical value(s), conclusion about the null hypothesis, and final conclusion that addresses the original claim. Cardiac Arrest at Day and Night A study investigated survival rates for in-hospital patients who suffered cardiac arrest. Among 58,593 patients who had cardiac arrest during the day, 11,604 survived and were discharged. Among 28,155 patients who suffered cardiac arrest at night, 4139 survived and were discharged (based on data from “Survival from In-Hospital Cardiac Arrest During Nights and Weekends,” by Peberdy et al., Journal of the American Medical Association, Vol. 299, No. 7). We want to use a 0.01 significance level to test the claim that the survival rates are the same for day and night. a. Test the claim using a hypothesis test. b. Test the claim by constructing an appropriate confidence interval. c. Based on the results, does it appear that for in-hospital patients…arrow_forward
- Functions and Change: A Modeling Approach to Coll...AlgebraISBN:9781337111348Author:Bruce Crauder, Benny Evans, Alan NoellPublisher:Cengage Learning