Sampling Exercises Chapters 1-4 n men finger 1. The Division of Traffic and Parking at a large university wants to know the percentage of students who used the campus bus system last week. They take a random sample of four hundred students from their list of students with parking stickers and find that 20% of them have used the bus system during the past week. The results of this survey are reported as follows: "With 95% confidence, the percentage of students using the bus system lies in the range 20% ± 4%." a. Identify each of the following: parameter population sample sample statistic level of confidence margin of error sampling frame and the b. This survey is likely to be biased because: i) the sampling frame is not the same as the population. ii) the margin of error is too large. ii) of nonresponse bias Pick one and briefly explain (including a statement of whether the problem is a type of sampling error or a type of non-sampling error). 2. A rand

C. Predicting Student Success STA believes there is a relationship between high school GPA (on a four-point scale) and college performance (as measured by GPA on a four-point scale). The following data were randomly selected from among students enrolling Fall 2020. HS GPA STA GPA Student 1 HS GPA STAGPA Student 21 2.9 2.5 3.6 3.4 2 3.4 3.1 3.0 22 3.4 4.0 1.7 3 3.1 23 2.9 2.9 1.7 3.0 3.2 3.3 4 24 3.5 5 3.4 25 4.0 3.6 3.6 3.0 26 3.6 3.8 3.2 3.9 3.1 27 8. 4.0 3.9 28 3.4 3.6 3.2 9. 3.0 3.0 29 3.7 10 2.9 2.0 3.0 30 4.0 3.3 4.0 3.2 11 3.3 31 12 3.6 3.8 32 3.7 3.2 3.4 3.0 13 3.7 3.9 33 14 3.8 3.6 34 2.5 2.0 15 2.5 2.5 35 2.9 2.9 3.7 2.2 16 2.9 2.5 36 3.8 17 2.8 2.1 37 2.9 18 3.8 1.7 3.5 38 3.6 3.5 3.6 19 3.7 39 3.6 20 3.9 3.0 40 3.1 3.6 Is high school GPA a good predictor of STA GPA? Why? What STA GPA would you predict for a student with a high school GPA of 3.75? How you would make the prediction.

Sample surveys on sensitive issues can give different results depending on how the question is asked. A University of Wisconsin study randomly divided 2400 respondents into three groups. All participants were asked if they had ever used cocaine. One group of 800 was interviewed by phone; 21% said they had used cocaine. Another 800 people were asked the question in a one-on-one personal interview; 25% said “Yes.” The remaining 800 were allowed to make an anonymous written response; 28% said “Yes.”101. Was this an experiment or an observational study? Justify your answer.2. Make a two-way table of responses about cocaine use by how the survey was administered.3. Are the differences between the three groups statistically significant? Give appropriate evidence to support your answer

1. A scientist is studying the effect of exercise on blood pressure. He studies 50 people who exercise regularly to find out whether their blood pressures are low, average, or high. This is an example of a(n): Answer choices: sample survey. observational study. experiment.

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The director of student services at Oxnard College is interested in whether women are less likely to attend orlentation than men before they begin their coursework. A random sample of freshmen at Oxnard College were asked what their gender is and whether they attended orientation. The results of the survey are shown below: Data for Gender vs. Orlentation Attendance Women Men Yes 426 491 No 190 189 What can be concluded at the a = 0.10 level of significance? For this study, we should use Select an answer a. The null and alternative hypotheses would be: Ho: Select an answery Select an answerv Select an answerv (please enter a decimal and note that p1 and ul represent the proportion and mean for women and p2 and u2 represent the proportion and mean for men.) H: Select an answerv Select an answerv Select an answerv (Please enter a decimal) b. The test statistic ?v = (please show your answer to 3 decímal places.) c. The p-value = (Please show your answer to 4 decimal places.) d. The p-value…

A real-estate appraiser wants to verify the market value for homes on the east side of the city that are very similar to size and style. The appraiser wants to test the popular belief that the average sales price is $37.80 per square foot for such homes. Suppose that a random sample of six sales were selected. The sampled sales prices per square foot are $35.00, $38.10, $37.20, $29.80, $30.30, and $35.40. Assuming a normal distribution is a good model for sales, test the claim that the mean sales price per square foot differs from $37.80 at the 1% significance level.

You may need to use the appropriate technology to answer this question. During the first 13 weeks of the television season, the Saturday evening 8:00 p.m. to 9:00 p.m. audience proportions were recorded as ABC 31%, CBS 26%, NBC 27%, and independents 16%. A sample of 300 homes two weeks after a Saturday night schedule revision yielded the following viewing audience data: ABC 97 homes, CBS 68 homes, NBC 91 homes, and independents 44 homes. Test with a = 0.05 to determine whether the viewing audience proportions changed. State the null and alternative hypotheses. 0.31, PCBS = 0.26, PNBC = 0.27, PIND 0.27, PIND = 0.16. Ho: : The proportions are not pPABC Наi РАВС 3 0.31, РсвS 0.26, PNBC 0.16 0.27, 0.16 Но: РАВС 0.31, Рсвs 3D 0.26, Наi РАВС + 0.31, РсвS PNBC + 0.26, PNBC ± 0.27, , PIND + 0.16 Ho: PABC + 0.31, PCBS + 0.26, PNBC + 0.27, PIND + 0.16 0.26, PNBC 0.27, PIND = 0.16 %D На РАВС - 0.31, РсBs 0.26, PNBC 0.27, PIND 0.16 Нo: РАВС - 0.31, РсBS H: The proportions are not PABC 0.16. 0.31,…