Descriptions of three studies are given. In each of the studies, the two populations of interest are students majoring in science at a particular university and students majoring in liberal arts at this university. For each of these studies, indicate whether the samples are independently selected or paired. Study 1: To determine if there is evidence that the mean number of hours spent studying per week differs for the two populations, a random sample of 100 science majors and a random sample of 75 liberal arts majors are selected.   (Independently selected/ Paired)?   Study 2: To determine if the mean amount of money spent on textbooks differs for the two populations, a random sample of science majors is selected. Each student in this sample is asked how many units he or she is enrolled in for the current semester. For each of these science majors, a liberal arts major who is taking the same number of units is identified and included in the sample of liberal arts majors.   (Independently selected/ paired)?   Study 3: To determine if the mean amount of time spent using the campus library differs for the two populations, a random sample of science majors is selected. A separate random sample of the same size is selected from the population of liberal arts majors.   (Indpendently selected/ paired)?

We are interested in analysing the effect of the lockout laws introduced in some areas of the Sydney CBD and nearby surrounds on the number of alcohol-related violent incidents.  Suppose we have two samples of data on the number of violent incidents in a number of local areas of the Sydney CBD and nearby surrounds. Pubs, hotels and clubs located in a subset of these areas became subject to the lockout laws when they were introduced in 2014. The first sample is from 2010 before the introduction of the lockout laws, and the second is from 2015 after the introduction of the law. The hypothesis we wish to test is that the introduction of the lockout laws reduces violent incidents in the areas in which the lockout laws were put in place.  We use a difference-in-difference model on the pooled data from 2010 and 2015. We find the following results: viol_inc hat = 33.21 (5.29) + 12.43lockout (7.01) – 4.19Yr2015 (2.98) – 3.32 (lockout x Yr2015) (1.85) N = 181, R^2 = 0.128 Where: viol_incis the…

For which of the following would it be most appropriate to use an ANOVA to analyze the data?    A researcher is interested in determining the most effective format for advertising. He randomly assigns 60 people to one of three groups: (1) television commercial, (2) radio commercial, or (3) magazine advertisement. Group members review the commercial and then report whether or not they would buy the product.  In order to determine the effectiveness of different diet plans, 90 people are randomly assigned to one of three groups: (1) low calorie diet, (2) low-fat diet, or (3) low-carb diet. At the end of 60 days, the number of pounds lost was recorded for each of the participants.  Both A and B.  Neither A nor B.

10) The following table shows the sample subjects cross-classified by gender and the type of violent victimization reported. Can we conclude on the basis of these data that victimization status and gender are not independent? Let a =0.01. Gender Women Men Total No victimization 611 308 919 Partner 42 20 62 Non-partner 16 17 33 Total 669 345 1014

The following table shows the ethnic origins of two random samples of students from a Canadian university, one from 2012 and the other from 2022: European 2012 2022 African Asian 308 58 52 364 100 58 Note: Canadian born students are classified according to their ancestry. (a) What would be an appropriate test to check if there has been an overall change in the distribution of ethnic origins among the student population of that university between 2012 and 2022? Justify your answer. ] Other 22 38 (b) Based on your answer in (a) above, test whether there has been an overall change in the distribution of ethnic origins among the student population of that university between 2012 and 2022. Use a 5% significance level and show your detailed manual calculations and all the steps of your hypothesis test (hypotheses, significance level, expected cell frequencies (rounded to 1 decimal), test statistic, decision criteria, critical value and p-value, conclusion with justification). (Manual…

When an audit must be conducted that involves a tedious examination of a large inventory, the audit may be very costly and time consuming if each item in the inventory must be examined. In such situations, the auditor frequently obtains a random sample of items from the complete inventory and uses the results of an audit of the sampled items to check the validity of the company's financial statement. A large company’s financial statement claims an inventory that averages $600 per item. The following data are the auditor’s assessment of a random sample of 75 items from the company’s inventory. The values resulting from the audit are rounded to the nearest dollar. Estimate the mean value of an item in the inventory using a 95% confidence interval. Is there substantial evidence (a 5 .01) that the mean value of an item in the inventory is less than $600? What is the target population for the above inferences? Would normal distribution–based procedures be appropriate for answering the…

A. For which data set is the sample correlation coefficient r closest to −1? B. For which data set is the sample correlation coefficient r closest to 0? C. For which data set is the sample correlation coefficient r equal to 1?

Twelve HSS students have been randomly assigned to one of three different statistics classes: one is taught by Professor Lavigne, another is taught by a monkey, and the last group has no professor and requires that students learn on their own. Here are the data:  Final grade in class:  Prof Lavigne: 67,74,82,55 Monkey: 43,66,52,10 No professor: 97,87,86,78 We now want to figure out if the average final grade in each class is different from one another. What kind of analysis does this require? One-way ANOVA A series of two-sample t-tests A series of one-sample t-tests None of the above What degrees of freedom are needed to answer the following question: Are average final grades statistically different in each group? 10 11 2 and 9 3 and 12 No degrees of freedom can be used

A father is concerned that his teenage son is watching too much television each day, since his son watches an average of 2 hours per day His son says that his TV habits are no different than those of his friends. Since this father has taken a stats class, he knows that can actually test to see whether or not his son is watching more TV than his peers The father collects a random sample of watching times from boys at his son's high school and gets the following data: 1.9, 2.3, 2.2, 1.9, 1.6, 2.6, 1.4, 2.0, 2.0, 2.2 Find a 95% confidence interval for the true mean number of hours teenagers at that school watch TV. a. Confidence Interval b. Conclusion

Five observations taken for two variables follow. xi 6 11 15 21 27 yi 6 9 5 18 12 a. compute the sample covarinace  b. Compute the sample correlation coefficient. (Round your answer to three decimal places.)