A study was performed to test the effectiveness of aspirin in the treatment of strokes. There were 155 patients in the study. A random sample of 78 of these patients were placed in the “aspirin” group, and the remaining 77 in the “control” group. After six months of treatment, all the patients were evaluated and their condition recorded as either favorable or unfavorable. Of the 78 “aspirin” patients, 63 had favorable outcomes; of the 77 “control” patients, 43 had favorable outcomes. We want to test the null hypothesis that the percentage of favorable outcomes is the same between the two conditions. (a) Write down the box model for the null hypothesis as a sentence or picture of the box. (b) Under the null hypothesis, the difference in the sample percentages is expected to be ________%, and the standard error for the difference is ________%. (c) Calculate the appropriate two-sample z test statistic.

A study was performed to test the effectiveness of aspirin in the treatment of strokes. There were 155 patients in the study. A random sample of 78 of these patients were placed in the “aspirin” group, and the remaining 77 in the “control” group. After six months of treatment, all the patients were evaluated and their condition recorded as either favorable or unfavorable. Of the 78 “aspirin” patients, 63 had favorable outcomes; of the 77 “control” patients, 43 had favorable outcomes. We want to test the null hypothesis that the percentage of favorable outcomes is the same between the two conditions. (a) Write down the box model for the null hypothesis as a sentence or picture of the box. (b) Under the null hypothesis, the difference in the sample percentages is expected to be %, and the standard error for the difference is %. (c) Calculate the appropriate two-sample z test statistic.

Holt Mcdougal Larson Pre-algebra: Student Edition 2012

1st Edition

ISBN:9780547587776

Author:HOLT MCDOUGAL

Publisher:HOLT MCDOUGAL

Chapter11: Data Analysis And Probability

Section: Chapter Questions

Problem 8CR

See similar textbooks

Similar questions

A survey of 900 adults from a certain region asked, "If purchasing a used car made certain upgrades or features more affordable, what would be your preferred luxury upgrade?" The results indicated that 57% of the females and 46% of the males answered window tinting. The sample sizes of males and females were not provided. Suppose that of 300 females, 171 reported window tinting as their preferred luxury upgrade of choice, while of 600males, 276 reported window tinting as their preferred luxury upgrade of choice. a. Determine the zstat, and the p-value. b.Determine the critical values and a conclusion c. Construct a 95% confidence interval estimate of the difference between the two population proportions.
In a small study, a local community college investigated different indicators of college success. They found that: 0.36 of enrolled students had a full time job, 0.75 of enrolled students were enrolled full-time, and 0.19 of students enrolled full-tme also had a full-time job. According to the results of this study, are the outcomes "have a full-time job" and "enrolled full-time independent?
A random sample of 148 small businesses was taken. During a 5 year time frame, 16 of the 106 businesses headed by men failed, and the 6 of the 42 headed by women failed. Find the p's (success) and q's (failures) of the study.
A consumer advocacy group wanted to study whether different airline carriers differed in terms of their delayed flights. In particular, the researchers were interested in the relationship between p1, the proportion of Alpha Airlines flights that were delayed at least 15 minutes, and p2, the proportion of Beta Airlines flights that were delayed at least 15 minutes. A random sample of 1,000 Alpha flights and a separate random sample of 1,000 Beta flights found that 67 of the Alpha fights and 160 of the Beta flights were delayed at least 15 minutes. The conditions for inference were checked and verified. Does this set of samples provide strong evidence that Alpha Airlines has a smaller proportion of flights that are delayed at least 15 minutes than Beta Airlines, at the α = 0.05 significance level? Find the z-table here. A. The test statistic is z = –6.56 and the P-value ≈ 0. Since the P-value ≈ 0 < 0.05, there is not sufficient evidence that Alpha Airlines has fewer delayed…
An article from the American Journal of Public Health reports the results from a randomized study designed to evaluate the efficacy of an intervention targeted to Hispanic/Latino men who identify as gay, bi-sexual or other men who have sex with men (MSM). A representative sample of 254 such men was randomized to be in either the intervention group (n=152, with 141 ultimately participating in the study) or the control group (n=152, with 147 ulitmately participating in the study). The primary outcome under study getting tested for HIV within the six-months following group assignment (randomization) among those who had been sexually active in this same six-month follow-up period. At six months of follow-up, 141 subjects in the intervention group reported having had sex (with men and/or women) since randomization. Of these 141 men, 114 had been tested for HIV since being randomized. At six months of follow-up, 147 subjects in the control group reported having had sex (with men…
A 1980 study investigated the relationship between the use of OCs and the development of endometrial cancer. The researchers found that of 117 endometrial-cancer patients, 6 had used the OC Oracon at some time in their lives, whereas 8 of the 395 controls had used this agent. Test for an association between the use of Oracon and the incidence of endometrial cancer, using a two-tailed test.
A study was performed to investigate whether teens and adults had different habits when it comes to consuming meat-free meals. In particular, the researchers were interested in the relationship between p1, the proportion of teens who would report eating at least one meat-free meal in the past week, and p2, the proportion of adults who would report eating at least one meat-free meal in the past week. A random sample of 875 teens and a separate random sample of 2,323 adults found that 555 of the teens and 1,601 of the adults reported eating at least one meat-free meal in the past week. The conditions for inference were checked and verified. The z-statistic for this hypothesis test was z = –2.95. Based on this z-statistic, what is the P-value and what is the conclusion the researchers should reach for this test? A. The P-value = 0.0016 and, because this P-value is very small, the conclusion should be that teens and adults differ in the proportion of their meat-free meals. B. The…
Do well-rounded people get fewer colds? A study on the Chronicle of Higher Education was conducted by scientist at Carnegie Mellon University, the University of Pittsburgh and the University of Virginia. They found that people who have only a few social outlets get more colds than those who are involved in a variety of social activities. Suppose that of the 276 healthy men and women tested, n1=96 had only a few social outlets and n2=105 were busy with six or more activities. When these people were exposed to a cold virus, the following results were observed: Construct a 99% confidence interval for the difference in the two population proportions.
A hearing specialist conducts a study on hearing loss at certain frequencies among a group of patients in a retirement community. Of 94 residents tested, 10 had significant hearing loss at low frequencies but not high, 40 had a significant loss at high frequencies but not low, and 26 showed no significant hearing loss at all. How many residents had hearing loss at both low and high frequencies?
A study of “adverse symptoms” in users of over-the-counter pain relief medications assigned subjects at random toone of two common pain relievers: acetaminophen and ibuprofen. In all, 650 subjects took acetaminophen, and 44experienced some adverse symptom. Of the 347 subjects who took ibuprofen, 49 had an adverse symptom. Is thisconvincing evidence that the two pain relievers differ in the proportion of people who experience an adverse symptom?
A researcher conducted a medical study to investigate whether taking a low-dose aspirin reduces the chance of developing colon cancer. As part of the study, 1,000 adult volunteers were randomly assigned to one of two groups. Half of the volunteers were assigned to the experimental group that took a low-dose aspirin each day, and the other half were assigned to the control group that took a placebo each day. At the end of six years, 15 of the people who took the low-dose aspirin had developed colon cancer and 26 of the people who took the placebo had developed colon cancer. At the significance level α = 0.05, do the data provide convincing statistical evidence that taking a low-dose aspirin each day would reduce the chance of developing colon cancer among all people similar to the volunteers?
A study is made of residents in Phoenix and its suburbs concerning the proportion of residents who subscribe to Sporting News. A random sample of 90 urban residents showed that 12 subscribed, and a random sample of 97 suburban residents showed that 17 subscribed. Does this indicate that a higher proportion of suburban residents subscribe to Sporting News? Use a 1% level of significance