A new medical test is designed to quickly detect whether someone is infected by SARS or not. The test result could be either positive or negative. A group of1250 persons have gone through the test among which 1175 are free of SARS infection. Among the 1175 healthy people, 1170 of them return negative test results; while among the remaining infected people, 73 of them return positive test results. Based on the above information, if positive test result is returned for another person, is he/she infected by SARS or not?

The drug X is marketed to help protect against male pattern baldness, and it also may protect against prostate cancer. A large sampleof healthy men over age 60 were randomly assigned to receive either a daily drug X pill or a placebo. The study lasted nine years and the men had annual check-ups and a biopsy at the end of the study. Prostate cancer was found in 815 of 4368 men taking drug X and in 1176 of the 4698 men taking a placebo. What kind of a study is this and what mesure of assocation (rd, rr, or) can be used and why?

The Consumer Reports Restaurant Customer Satisfaction Survey is based upon 148,599 visits to full-service restaurant chains (Consumer Reports website). One of the variables in the study is meal price, the average amount paid per person for dinner and drinks, minus the tip. Suppose a reporter for the Sun Coast Times thought that it would be of interest to her readers to conduct a similar study for restaurants located on the Grand Strand section in Myrtle Beach, South Carolina. The reporter selected a sample of 8 seafood restaurants, 8 Italian restaurants, and 8 steakhouses. The following data show the meal prices ($) obtained for the 24 restaurants sampled. Use a = 0.05 to test whether there is a significant difference among the mean meal price for the three types of restaurants. Please answer the questions in the image.

A researcher wanted to test whether people tended to trust people who smiled more than people who did not smile. To test that, she collected a sample of fifty people and presented each of them with 48 pairings of photos. Each pairing was made of one photo of a smiling person, and another photo of a person who was not smiling. The subjects were asked to select the person they trusted more. For each subject, the researcher measured the number of times a smiling person was selected. Based on the null hypothesis, what should be the mean number of times a smiling person is selected? 1. 48 2. 25 3. 50 4. 24

People who work out vigorously for an hour or more experience loss of electrolytes such as calcium, potassium, and sodium that are released from the body by sweat. Potassium is a very important part of many bodily functions for athletes, including transmitting nerve signals and fluid balance. A random sample of 9 athletes were given water after a vigorous one-hour workout and their electrolytes were then checked and recorded. After another vigorous one-hour workout on a different day, the same 9 athletes’ electrolytes were checked after being given a sports drink. Their potassium levels are given below. Do sports drinks help replenish lost potassium levels more than water after a vigorous workout? Refer to the table below. Water: 4.17, 2.88, 4.71, 4.79, 5.11, 4.12, 3.95, 4.22, 3.86 Sports Drink: 4.20, 3.30, 4.69, 4.82, 5.17, 4.08, 4.49, 4.54,3.71 hypothesis test needed Hypothesis test needed

In the Star and Tribune newspaper, there is an article entitled "1 in 8 school buses fail tests." The article says that the overall statewide proportion of school buses that fail safety tests is 9%. However, one bus company has a higher rate of over 12%. Assume that we want a new estimate for the statewide proportion of school buses that fail the safety inspection. We take a sample of 500 buses and find that 90 buses fail the safety inspection. Based on the new sample data, I construct this 90% confidence interval estimate for p: 152 < p < .208. Explain what this confidence interval means. O I am 90% sure that the number of buses that fail the inspection is between.152 and .208. O I am 95% sure that the true proportion of buses that fail the inspection is between .152 and .208. O I am 90% sure that the proportion of buses in this sample that fail the inspection is between .152 and .208. O I am 90% sure that the true proportion of buses that fail the inspection is between .152 and .208.

A study in 2001, asked 792 college-age kids if they are attending a college and whether at least one of their parents had a college degree. Out of 445 college students, 214 stated that their parents did not have a college degree, and out of 347 teens not enrolled in a college, 298 indicated that their parents did not have a college degree. We would like to determine if the proportion of parents with no college-degree for teens who are not enrolled in a college is the same as that for teens who are enrolled in a college. 20.State the null and alternative hypothesis for this investigation in complete sentences and as mathematical equations. 21. Find the point estimate for the parameter of interest for this investigation. 22. Find the test statistic for this investigation. 23. Find the p-value for this investigation. 24. State the conclusion of this investigation in context.

A researcher is interested in factors related to academic performance of students.  She hypothesized that for undergraduate students, there is an association between academic majors (STEM, Business, Education, Nursing) and amount of time spent studying each week (less than 3 days, 3 to 6 days, everyday).  To test her hypothesis, she randomly selected 1000 undergraduate students from various colleges/universities in Texas, and then classified each participant according to their major and amount of study time each week.  For her study, she found test-statistic of 23.75 and a p-value of 0.0006.  Using this information, fill in the necessary information below for her test. Distribution used:    a. chi-square distribution, 3 degrees of freedom   b. chi-square distribution, 4 degrees of freedom   c. chi-square distribution, 6 degrees of freedom   d. chi-square distribution, 12 degrees of freedom

Alcohol abuse has been described by college presidents as the number one problem on campus, and it is an important cause of death in young adults.  How common is it?  A survey of 10,904 randomly selected U.S. college students collected information on drinking behavior and alcohol-related problems.  The researchers defined “frequent binge drinking” as having five or more drinks in a row three or more times in the past two weeks.  According to this definition, 2486 students were classified as frequent binge drinkers.  Construct and interpret a 99% confidence interval for the proportion of students who are classified as binge drinkers. (Use the four-step process and Table A to get your z* value.)   Using the interval that you calculated in the last question, conclude in context for the question.

The national Park service monitors streams in Rainier national park for pollution and fish spawning habits. Suppose it is known that 40% of the streams in the park are either considered "polluted" or "known for spawning stream", 15% of the streams are classified as "polluted" and 35% of the streams are "known for spawning streams" what proportion of streams are known to be both polluted and known for spawning streams.