Concept explainers
Exercises 33 through 36 refer to the following story: The manufacturer of a new vitamin (vitamin X) decides to sponsor a study to determine the vitamin's effectiveness in curing the common cold. Five hundred college students having a cold were recruited from colleges in the San Diego area and were paid to participate as subjects in this study. The subjects were each given two tablets of vitamin X a day. Based on information provided by the subjects themselves,
a. Describe as specifically as you can the target population for the study.
b. Describe the sampling frame for the study.
c. Describe the sample used for the study.
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MYLAB MATH FOR EXCURSIONS IN MATHEMATIC
- Study 1: A study of 300 high school students was done. Half of them were instructed to drink soda every day. The other half was instructed to not drink soda at all. After one month, the half that were drinking soda had gained an average of five pounds more than the half that did not drink soda. b. Is there a control group and experimental group?arrow_forwardA certain virus affects 0.5% of the population. A test used to detect the virus in a person is positive 90% of the time if the person has the virus (true positive) and 15% of the time if the person does not have the virus (false positive). Fill out the remainder of the following table and use it to answer the two questions below based on a total sample of 100,000 people. Virus No Virus Total Positive Test Negative Test Total 100,000 a) Find the probability that a person has the virus given that they have tested positive. Round your answer to the nearest hundredth of a percent and do not include a percent sign. % b) Find the probability that a person does not have the virus given that they test negative. Round your answer to the nearest hundredth of a percent and do not include a percent sign.arrow_forwardWeek 4 2. In a study concerned with the possible effects of air pollution on the development of chronic bronchitis, the following data were obtained. A population of 15,000 men between 40 and 50 years old was examined in January 2010. Of these, 10,000 lived in areas that exposed them to air pollution and 5,000 did not. At this examination, 250 cases of chronic bronchitis were discovered in the total study population. Of these 250 cases, 195 were among those exposed to air pollution. All the men initially examined who did not have chronic bronchitis were available for repeated examinations after five years. These examinations revealed 725 new cases of chronic bronchitis in the total group, which included 175 among those not exposed to air pollution. a. Calculate the prevalence rates of chronic bronchitis at the January 2010 examination for the total sample, the group exposed to air pollution, and the group not exposed to air pollution. Note: Calculate a point prevalence. Your answer…arrow_forward
- The following is based on information from The Wolf in the Southwest: The Making of an Endangered Species, by David E. Brown (University of Arizona Press). Before 1918, the proportion of female wolves in the general population of all southwestern wolves was about 50%. However, after 1918, southwestern cattle ranchers began a widespread effort to destroy wolves. In a recent sample of 37 wolves, there were only 11 females. One theory is that male wolves tend to return sooner than females to their old territories, where their predecessors were exterminated. Do these data indicate that the population proportion of female wolves is now less than 50% in the region? Use α = 0.01. (a) What is the level of significance? State the null and alternate hypotheses. O Ho: P 0.5 O Ho: P = 0.5; H₁: p 5 and nq > 5. O The Student's t, since np > 5 and ng > 5. The standard normal, since np < 5 and nq < 5. O The Student's t, since np < 5 and nq < 5. What is the value of the sample test statistic? (Round…arrow_forwardThe following is based on information from The Wolf in the Southwest: The Making of an Endangered Species, by David E. Brown (University of Arizona Press). Before 1918, the proportion of female wolves in the general population of all southwestern wolves was about 50%. However, after 1918, southwestern cattle ranchers began a widespread effort to destroy wolves. In a recent sample of 37 wolves, there were only 11 females. One theory is that male wolves tend to return sooner than females to their old territories, where their predecessors were exterminated. Do these data indicate that the population proportion of female wolves is now less than 50% in the region? Use a = 0.01.arrow_forwardThe following is based on information from The Wolf in the Southwest: The Making of an Endangered Species, by David E. Brown (University of Arizona Press). Before 1918, the proportion of female wolves in the general population of all southwestern wolves was about 50%. However, after 1918, southwestern cattle ranchers began a widespread effort to destroy wolves. In a recent sample of 37 wolves, there were only 11 females. One theory is that male wolves tend to return sooner than females to their old territories, where their predecessors were exterminated. Do these data indicate that the population proportion of female wolves is now less than 50% in the region? Use a = 0.01. (a) What is the level of significance? State the null and alternate hypotheses. O Ho: p 0.5 (b) What sampling distribution will you use? O The Student's t, since np 5 and nq > 5. O The Student's t, since np > 5 and ng > 5. What is the value of the sample test statistic? (Round your answer to two decimal places.)…arrow_forward
- A pharmaceutical company conducts an experiment to test the effect of a new cholesterol medication. The company selects 15 subjects randomly from a larger population. Each subject is randomly assigned to one of three treatment groups. Within each treatment group, subjects receive a different dose of the new medication. In Group 1, subjects receive 0 mg/day; in Group 2, 50 mg/day; and in Group 3, 100 mg/day. After 30 days, doctors measure the cholesterol level of each subject. The results for all 15 subjects appear in the table below: Dosage Group 1 Group 2 Group 3 O mg 50 mg 100 mg 210 210 180 240 240 210 270 250 220 270 270 210 300 270 240 (a) Perform an appropriate test to test whether there are differences among the mean cholesterol level by three different doses of the new medication at 5% level of significance. (b) Compute the p-value and indicate whether it leads to the same conclusion.arrow_forwardWhat is the minimum number of passengers to contract the virus?arrow_forwardA clinical psychologist wants to test the effectiveness of three new therapies that have been developed for reducing anxiety symptoms. The researcher recruits 15 participants and randomly assigns them to take part in Therapy A, Therapy B, or Therapy C for a month. At the end of the month, the researcher measures the participants' anxiety symptoms on a scale from 1 to 10 (where a higher score means more anxiety symptoms). The participants' scores are shown below: What is the appropriate test to use ? 3. What are the null and alternative hypotheses ? 4. Using a two-tailed alpha of .05, determine what the critical value is 5. Calculate the test statistic 6. State whether you reject or fail to reject the null hypothesis for the omnibus test 7. Calculate and report the effect size for the omnibus test 8. Perform a Post-Hoc Test. Report the significance of each pairwise comparisonarrow_forward
- Do people feel hungrier after sampling a healthy food? The authors of a consumer research paper carried out a study to answer this question. They randomly assigned volunteers into one of three groups. The people in the first group were asked to taste a snack that was described as a new health bar containing high levels of protein, vitamins, and fiber. The people in the second group were asked to taste the same snack but were told it was a tasty chocolate bar with a raspberry center. After tasting the snack, participants were asked to rate their hunger level on a scale from 1 (not at all hungry) to 7 (very hungry). The people in the third group were asked to rate their hunger but were not given a snack. The data in the table are consistent with summary quantities given in the paper (although the sample sizes in the actual study were larger). Treatment Group Healthy Tasty 5 8 7 Hunger Rating No Snack 3 4 4 4 1 4 2 7 3 6 2 5 6 5 5 4 7 5 2 3 4 6 4 4 Sample Mean 5.6667 3.4444 4.2222 Sample…arrow_forwardDo people feel hungrier after sampling a healthy food? The authors of a consumer research paper carried out a study to answer this question. They randomly assigned volunteers into one of three groups. The people in the first group were asked to taste a snack that was described as a new health bar containing high levels of protein, vitamins, and fiber. The people in the second group were asked to taste the same snack but were told it was a tasty chocolate bar with a raspberry center. After tasting the snack, participants were asked to rate their hunger level on a scale from 1 (not at all hungry) to 7 (very hungry). The people in the third group were asked to rate their hunger but were not given a snack. The data in the table are consistent with summary quantities given in the paper (although the sample sizes in the actual study were larger). TreatmentGroup Hunger Rating SampleMean SampleStandardDeviation Healthy 5 8 7 4 7 3 4 7 6 5.6667 1.7321 Tasty 4 1 5 2 6 2 5 3 4 3.5556…arrow_forwardA company wishes to evaluate the effect of package design on one of its products, a certain brand of cereal. The four package designs are to be tested in different stores throughout a large city. There are 20 stores available for the study. The amount of cereal sold is known to vary depending on the size of the stores. The 20 stores are divided into five groups of four stores each by size. The following sales figures ($1000s) were obtained after a 1-month period. Stores Design A Design B Design C Design D 1 40 33 37 38 2 45 27 32 40 3 43 31 30 41 4 44 38 40 42 5 56 45 49 42 Enter the above data into a suitable software and then conduct an analysis of variance without blocking to test whether there is evidence of a significant difference in mean sales of different package designs. Use alpha = 0.01. What are the mean squares for error? Please provide your answer to the nearest two decimal places.arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill