Stats 315 Test 1 Homework Questions

An online ad for Dr. Mary Hart, a renowned cardiologist, states, 'in a survey of Dr. Hart's patients, 96% of a random sample of her patients say they would recommend Dr. Hart to other patients.' Based on this data, which of the following conclusions are valid? Select all that apply. A. 4% of Dr. Hart's patients do not recommend her. B. 96% of all patients recommend Dr. Hart C. About 96% of Dr. Hart's patients recommend her. D. Exactly 96% of all Dr. Hart's patients would recommend her. E. None of the above

A

The school lunch committee at Bayside High wants to determine what types of vegetables to serve in the cafeteria. As part of their survey, they ask all members of the Bayside boy's baseball team the question 'Do you like broccoli?' 15% of the team responds 'yes'. Based on this data, which of the following conclusions are valid? Select all that apply. A. Exactly 15% of all students on the boys baseball team at Bayside High like broccoli. B. About 15% of all students at Bayside High like broccoli. C. 15% of the students on the baseball team at Bayside High like all vegetables. D. 15% of the students on the baseball team at Valley High (Bayside's main rival in baseball) like broccoli. E. None of the above

A

A pharmaceutical company wanted to check whether their new cough medicine really relieves coughs. To do that, they went over medical records of all clinics in the country and looked for an association between the type of medicine prescribed for patients who suffer from coughs and the level of their recovery. What is the objective of the company's study? A. They want to determine whether there is a correlation between taking the cough medicine and cough relief. B. They want to estimate the proportion of patients taking the cough medicine. C. They want to demonstrate that their cough medicine helps relieve coughs. Is the study appropriate for the statistical questions it's supposed to answer? Mark the most suitable choice. A. No, because the company didn't choose the clinics at random. B. No, because the type of study isn't appropriate for the question. C. No, because the study collects data of patients who took other medications. D. Yes, because the study assesses the connection between taking the cough medicine and cough relief.

AB

Part 2 The school board administered a math test to all students in grades 6-8 at Johnsonville Middle School and determined that 15% of them were below grade level in math. Based on this data, which of the following conclusions are valid? Select all that apply. A. 15% of all eighth-grade students at JMS are below grade level in math. B. 15% of all students in grades 6-8 at JMS are below grade level in math. C. 15% of all students in grades 6-8 in the district are below grade level in math. D. 15% of eighth-grade students in the district are below grade level in math. E. None of the above

B

Researchers were interested in the effect of pre-existing inappropriate highlighting of text on reading comprehension. They randomly assigned a group of 600 students to two groups. Both groups were asked to answer a reading comprehension test. The text given to the first group had inappropriate passages highlighted, while the text of the second group wasn't highlighted at all. Then, the researchers compared the average score of each group in the reading comprehension test. What is the objective of this study? A. The researchers want to estimate the level of reading comprehension in students. B. The researchers want to see if inappropriate highlighting causes student reading comprehension to decrease. C. The researchers want to see if there is a correlation between inappropriate highlighting and student reading comprehension. Is this study appropriate for the statistical questions it's supposed to answer? Mark the most suitable choice. A. No, because they actively interfered with the test of the first group, and therefore affected their test results. B. Yes, because they randomized the subjects between the groups and used an appropriate measure for the effect (the test scores). C. No, because the type of study they used was inappropriate. D. No, because maybe one of the groups has significantly better reading comprehension skills than the other group, regardless of the highlighted text.

BB

City Councilwoman Kelly wants to know whether the residents of her district support a proposed school redistricting plan. Which of the following survey methods will allow Councilwoman Kelly to make a valid conclusion about whether residents of her district support the proposed plan? Select all that apply. A. Ask her neighbors. B. Ask a group of parents at the local playground. C. Ask 200 residents of her district whose names are chosen at random. D. Ask the residents of Shady Acres Retirement Community. E. None of the above

C

Part 3 In a survey based on a random sample of 1000 customers, CableCom found that 42% of its customers are satisfied with CableCom's service. Based on this data, which of the following conclusions are valid? Select all that apply. A. Exactly 42% of those surveyed are satisfied with their service. B. Exactly 58% of all of CableCom's customers are not satisfied with their service. C. About 42% of all of CableCom's customers are satisfied with their service. D. Exactly 42% of all of CableCom's customers are satisfied with their service. E. None of the above

AC

Beth wants to go on a popular TV talent show. In order to be accepted, her audition must get at least 60% positive votes from people in the crowd. To make sure she's not going to embarrass herself, she performed her act in front of 100 random people from her school. About 90% of the people said they would give her a positive vote. She calculated the margin of error and found it's well within the range above 60%, so she decided to go to the audition. What is the objective of Beth's study? A. She wants to see if changing her performance leads to a more positive audience response. B. She wants to estimate a population parameter. C. She wants to sample the population to see if there is a correlation between her performance and the audience response. Is the study appropriate for the statistical questions it's supposed to answer? Mark the most suitable choice. A. No, because the population she sampled isn't necessarily representative. B. Yes, because the sample she used is big enough. C. Yes, because 90% is much higher than 60%, so she can be very confident she will be accepted. D. No, because the sample she used is not big enough.

BA

The taste engineers at 'Drinksoft' have developed a new formula for their major brand 'Cola-Loca.' They wanted to know how tasty it is to teenagers compared to the old formula, so they decided to set up a blind taste test. They randomly assigned 300 blindfolded, teenaged participants to two groups. One group was given the old formula of 'Cola-Loca' and the other was given the new formula. Each participant was asked to fill out a formal taste 10-point questionnaire, where 1 is considered 'awful' and 10 is considered 'delicious.' What is the objective of the engineers study? A. The engineers want to determine which formula of 'Cola-Loca' teenagers would select. B. The engineers want to determine whether teenagers think the new formula of 'Cola-Loca' is tastier than the old formula. C. The engineers want to determine how good the new formula tastes. The engineers found that the average taste score of the new formula is 4 points lower than the average taste score of the old formula. What valid conclusions can be made from this result? Mark the most suitable choice. A. There's a positive correlation between drinking the old formula and the perceived tastefullness among teenagers. B. The result suggests that the old formula tastes better among teenagers than the new one. C. The old formula tastes better than the new one. D. The result suggests that the old formula tastes better among teenage boys than the new one.

BB

Part 1 The city council of Helena wants to determine whether the residents favor a building plan for the town center. They will ask residents over 21 years of age, 'Do you favor the proposed building plan?' Which of the following methods of surveying the residents over 21 will allow the city council to make valid conclusions about the preferences of Helena's residents? Select all that apply. A. Ask all of the residents over 21 who live west of the train tracks B. Ask every resident over 21 years of age. C. Put all of the names of residents over 21 into a computer program and allow the program to generate 200 random names. Ask those residents. D. Ask 200 residents over 21 who are shopping at the mall on a particular Saturday. E. None of the above

CD