Comparing a census of a large population to a sample drawn from it, we expect that the
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Comparing a census of a large population to a sample drawn from it, we expect that the
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- . Suppose a researcher has heard that children watch an average of ten hours of TV per day. The researcher believes this is wrong but has no theory about whether it's an overestimate or an underestimate of the truth. If the researcher wants to do a z-test of one population mean, what will the researcher's alternative hypothesis be?Suppose that you would like to determine if the use of the newest Sweeney education intervention will improve students understanding of statistics better than the use of no intervention. In order to do this, you select two groups of students at random from students who need to take Statistics: a group given the intervention and another group that is given the standard statistics class. At the end of the course, the students were given an exam and the exam scores were compared. Group 1: Students given the interventionGroup 2: Students in the standard Statistics class Use this information to answer the following questions:a. What test should you run and why?b. What is the null hypothesis? What is the alternative hypothesis?c. What requirements would have to be met to insure that you could run the test?A statistics professor would like to build a model relating student scores on the first test to the scores on the second test. The test scores from a random sample of 21 students who have previously taken the course are given in the table. Student Test Grade 1 Test Grade 21 42 812 51 743 88 624 99 575 54 726 66 737 87 638 99 579 97 5810 89 6311 42 7712 71 6313 96 5514 56 7615 75 6916 57 7017 62 7518 89 6319 50 7220 56 7221 89 57Step 1 of 2 : Using statistical software, estimate the parameters of the modelSecond Test Grade=β0+β1(First Test Grade)+εi.Enter a negative estimate as a negative number in the regression model. Round your answers to 4 decimal places, if necessary.
- Tanner recently moved into a new neighborhood and was surprised by the large amount of trick ortreaters he received. He asked his neighbors and found out that in previous years they averaged about40 trick ortreaters each Halloween Tanner thinks this year there were a lot more. Below is the data that each house got this year:House 1 49House 2 48House 3 35House 4 53House 5 40 What statistical test should we use to test hypothesis? (Z-Test, One-Sample T-Test, Dependent Two-Sample, or Independent Two-Sample) Why?1:03 Done Knowledge Check Observed frequency fo Expected frequency SE (fo-ƒE)² JE expected frequencies to two or more decimal places. REspañol yo responses to three or more decimal places. Send data to Excel www-awu.aleks.com AA Monday Tuesday Wednesday Thursday 29 18 0 28.00 3.571 34 28.00 1.286 Type of test statistic: (Choose one) ▼ Z (b) Find the value of the t more decimal places.) □ all 100 28 28.00 (a) Determine the type of test statistic to use. Chi-square Friday Total 31 0 0.000 0 Evelyn V Ć 140 Part 2 Answer the following to summarize the test of the hypothesis employee absences at this firm are equally likely on each of th weekdays. Use the 0.05 level of significance for the test. E (Round your answer to two orA random sample of 300 physicians shows that there are 50 of them who make at least $200,000 a year. What is the test statistic if we want to test that the true proportion of physicians in the population who make at least $200,000 a year is less than 0.20?
- Julius has conducted a very small study of the amount of sleep his dorm mates get each night. He believes that those who are on one of the school’s sports teams will get more sleep (measured in hours per night) than those who are not. Julius surveyed 12 people. Of these, 6 played on a sports team and 6 did not. The descriptive statistics from his survey are given below. PLAYS SPORTS (Sample 1) DOES NOT PLAY SPORTS (Sample 2) 8 6 9 6 8 5 7 7 8 7 7 6 What is the critical value for this test? what is the t-obtain value for this t-test? Based on your t-obtained value, what should you conclude about the null hypothesis for this test?The price of a share of stock divided by the company's estimated future earnings per share is called the P/E ratio. High P/E ratios usually indicate "growth" stocks, or maybe stocks that are simply overpriced. Low P/E ratios indicate "value" stocks or bargain stocks. A random sample of 51 of the largest companies in the United States gave the following P/E ratiost. 9 20 11 35 19 13 15 21 29 53 16 26 21 14 21 27 10 12 47 14 40 18 60 72 33 14 8 49 5 16 8 19 12 31 67 51 26 18 17 20 19 13 25 23 27 44 20 27 19 18 32 (a) Use a calculator with mean and sample standard deviation keys to find the sample mean x and sample standard deviation s. (Round your answers to one decimal place.) (b) Find a 90% confidence interval for the P/E population mean u of all large U.S. companies. (Round your answers to one decimal place.) lower limit upper limit (c) Find a 99% confidence interval for the P/E population mean u of all large U.S. companies. (Round your answers to one decimal place.) lower limit upper…News reports speak of an emerging crisis of childhood obesity in the United States. The National Health and Nutrition Examination Survey (NHANES) is a government survey run every several years recording a number of vital statistics on a random sample of Americans. A body mass index (BMI) is computed for each individual in the sample based on the individual's height and weight. Here are sample results for 8-year-old boys over the past 40 years. The table gives the sample size for 3 different surveys, the sample mean and sample standard deviation. Suppose we want to run an ANOVA to see if there is a difference in mean BMI for the three surveys. Assume each survey is a random sample and there are no extreme outliers.What is the sample standard deviations for each survey? ...the NHES II study? ...the NHANES II study? ...the NHANES study?
- You may need to use the appropriate technology to answer this question. A certain manufacturer is a producer of aluminum components for the avionics and automotive industries. At its plant, an engineer has conducted a quality-control test in which aluminum coils produced in all three shifts were inspected. The study was designed to determine if the population proportion of good parts was the same for all three shifts. Sample data follow. Production Shift Quality First Second Third Good 282 364 172 Defective 18 36 28 (1) Using a 0.05 level of significance, conduct a hypothesis test to determine if the population proportion of good parts is the same for all three shifts. State the null and alternative hypotheses. A) H0: p1 = p2 = p3 Ha: Not all population proportions are equal. B) H0: p1 ≠ p2 ≠ p3 Ha: All population proportions are equal. C) H0: At least two population proportions are equal. Ha: p1 ≠ p2 ≠ p3 D) H0: Not all population proportions are equal. Ha: p1 =…Does it seem to you that people tend to be absent more on some days of the week than on others? Recently, a major biotechnology firm collected data with the hope of determining whether or not its employees were more likely to be absent on some weekdays than on others. The firm examined a random sample of 130 employee absences. The distribution of these 130 absences is shown in the table below. The observed frequency for each category (each weekday) is shown in the first row of numbers. The second row of numbers contains the frequencies expected for a sample of 130 employees if employee absences at the firm are equally likely on each of the five weekdays. The bottom row of numbers contains the following value for each of the categories.How do the average weekly incomes of electricians and carpenters compare? A random sample of 17 regions in the United States gave the following information about average weekly income (in dollars). (Reference: U.S. Department of Labor, Bureau of Labor Statistics.) Region 1 2 3 4 5 6 7 8 9 Electricians 464 715 597 464 736 694 744 571 806 Carpenters 542 813 513 476 688 503 789 653 474 Region 10 11 12 13 14 15 16 17 Electricians 592 594 702 579 868 598 597 654 Carpenters 489 647 676 384 817 605 556 505 Does this information indicate a difference (either way) in the average weekly incomes of electricians compared to those of carpenters? Use a 5% level of significance. (a) What is the level of significance? (b) Compute the sample test statistic. (c) Find the P-value of the sample test statistic.