Statistics Math 125 - Module 1 Quiz 1
Determine whether the following statement is true or false. Explain. A simple random sample is always preferred because it obtains the same information as other sampling plans but requires a smaller sample size.
False, because other sampling techniques may provide more information for less cost than a simple random sample.
A golf pro wanted to compare two types of golf clubs. One type is graphite dash shafted and the other is steel dash shafted. It is a common belief that graphite shafts give more distance. This belief is tested by having 10 golfers hit one ball with each type of club and then determining the distance that the ball traveled. A coin flip was used to determine which type of club each player would hit with first. Results indicated that there was no difference in the two types of club. Complete parts (a) through (f) below.
(a) What type of experimental design is this? Matched-pairs design (b) What is the response variable in this study? The distance (c) What is the factor that is set to predetermined levels? What is the treatment? The factor is the type of club. The treatments are graphite dash shafted and steel dash shafted (d) Identify the experimental units. Choose the correct answer below. The golfers (e) Why is a coin used to decide the club each player would hit with first? To eliminate bias as to which club was used first (f) Draw a diagram to illustrate the design. Choose the correct diagram below. Randomly assign each golfer to both treatments. Administer treatments and record distances. For each golfer compare the distances.
A pharmaceutical company wants to conduct a survey of 20 individuals who have high cholesterol. The company has obtained a list from primary care physicians throughout the country of 3600 individuals who are known to have high cholesterol. Design a sampling method to obtain the individuals in the sample. Be sure to support the choice
-Alphabetize the list of 3600 individuals by last name and select one of the first 180 individuals at random. Starting from the selected individual, read down the list and select every 180th individual. -Group the individuals by common primary care physician. For each group, assign all the individuals different numbers, and use a random number table to select an appropriate number of individuals. -Group the individuals by common primary care physician. Assign each physician a different number and use a random number table to select physicians until the total number of patients of all the selected physicians is at least 20.
Determine whether the study depicts an observational study or an experiment. Forty patients with skin cancer are divided into two groups. One group receives an experimental drug to fight cancer comma the other a placebo. After two years comma the spread of the cancer is measured.
Does the description correspond to an observational study or an experiment?The study is an experiment because the researchers control one variable to determine the effect on the response variable.
Twenty patients with leukemia are divided into two groups. One group is treated with an experimental drug. The other is not. After one month, both groups are questioned about their energy level.
Is the study an observational study or an experiment?The study is an experiment because the researchers control one variable to determine the effect on the response variable.
Determine whether the quantitative variable is discrete or continuous. Number of interceptions made by a defensive back
Is the variable discrete or continuous?The variable is discrete because it is countable
Determine whether the quantitative variable is discrete or continuous. Number of coins in a jar
Is the variable discrete or continuous?The variable is discrete because it is countable.
Suppose that a magazine predicted that Candidate A would defeat Candidate B in a certain election. They conducted a poll of telephone directories with a response rate of 24%. On the basis of the results, the magazine predicted that Candidate A would win with 57% of the popular vote. However, Candidate B won the election with about 62% of the popular vote. At the time of this poll, most households with telephones belonged to the party of Candidate A. Name two biases that led to this incorrect prediction
Sampling bias: Using an incorrect frame led to undercoverage. Nonresponse bias: The low response rate caused bias.
Suppose a random phone survey is being conducted to find the population's feelings on a new nothingice cream flavor. If the randomly selected person is not home comma they are called again later in the day.nothing What tactic is being used to increase the response rate for this survey?
The company is using call backs
Determine whether the study depicts an observational study or an experiment. Athletes are randomly divided into two groups. One group trains using weight resistance; the other trains using cardio. After 2 months comma each group completes a fitness test to compare agility. nothing
The study is an experiment because the researchers control one variable to determine the effect on the response variable.
Determine whether the underlined value is a parameter or a statistic. In a championship football game comma a quarterback completed Modifying 59 % with underline of his passes for a total of 265 yards and 2 touchdowns.
The value is a parameter because the quarterback's passes are a population.
The data on the right relate to characteristics of high-definition televisions A through E. Identify the individuals, variables, and data corresponding to the variables. Determine whether each variable is qualitative, continuous, or discrete.
What are the individuals being studied? The high-definition television setups A through E. What are the variables and their corresponding data being studied? Size (51, 60, 57, 40, 48), screen type (Plasma, Projection, Projection, Plasma comma Plasma), and number of channels available (298, 107, 422, 270, 290) Determine whether each variable is qualitative, continuous, or discrete. Size is a continuous variable. Screen type is a qualitative variable. Number of channels available is a discrete variable.
A poll is being conducted at an outlet store nothingto obtain a sample of the population of an entire country. What is the frame for this type of sampling? Who would be excluded from the survey and how might this affect the results of the survey?
What is the frame for this type of sampling? The frame is the entire population of the country Who would be excluded from the survey and how might this affect the results of the survey? Any person who does not shop at outlet stores is excluded. This could result in sampling bias due to undercoverage.
A quality-control manager randomly selects 60 bottles of orange juice that were filled on August 23 to assess the calibration of the filling machine.
What is the population in the study? All bottles of orange juice produced in the plant on August 23. What is the sample in the study? The 60 bottles of orange juice selected in the plant on August 23.
To determine customer opinion of their pricing, Greyhound Lines randomly selects 100 busses during a certain week and surveys all passengers on the busses.
What type of sampling is used? Cluster
A newspaper asks its readers to call in their opinion regarding the number of books they have read this month.
What type of sampling is used?Convenience
Sony wants to administer a satisfaction survey to its current customers. Using their customer database, the company randomly selects 70 customers and asks them about their level of satisfaction with the company.
What type of sampling is used?Simple random
To determine her mood, Denise divides up her day into three parts: morning, afternoon, and evening. She then measures her mood at 3 randomly selected times during each part of the day.
What type of sampling is used?Stratified
Consider the following question from a recent poll. Thinking about how the affirmative action issue might affect your vote for major offices, would you vote only for a candidate who shares your views on affirmative action or consider a candidate's position on affirmative action as just one of many important factors? [rotated] Why is it important to rotate the two choices presented in the question?
Which of the following is correct?The choices need to be rotated to minimize response biases
A club wants to sponsor a panel discussion on the upcoming national election. The club wants four of its members to lead the panel discussion. Write a short description of the processes that can be used to generate your sample. Obtain a simple random sample of size 4 from the table.
Which of the following would produce a simple random sample? Select all that apply. -Number the names from 1 to 25 and use a random number table to produce 4 different two digit numbers corresponding to the names selected. -List each name on a separate piece of paper, place them all in a hat, and pick four. Use the portion of the random number table provided to obtain a simple random sample of size 4 from this list. If you start with the first column of the first row, work down each column (if one must go back to the top of the table, do not skip any columns), and take the first four numbers between 1 and 25, what four members would be selected from the numbered list? Grajewski, Pawlak, Debold, Motola
The following survey has bias. (a) Determine the type of bias. (b) Suggest a remedy. Upper A magazine is conducting a study on the effects of infidelity in a marriage. The editors randomly select 400 women whose husbands were unfaithful and ask comma "Do you believe a marriage can survive when the husband destroys the trust that must exist between husband and wife question mark " nbsp nothing
(a) What is the type of bias? Response bias (b) What is a possible remedy?Reword the question.
The survey has bias. (a) Determine the type of bias. (b) Suggest a remedy. Suppose you are conducting a survey regarding activity level of children in a school district. You obtain a cluster sample of 24 schools within a school district and sample all sophomore students in the randomly selected schools. The survey is administered by the parents.
(a) Which of these best describes the bias in the survey?Response bias (b) How can the bias be remedied?The survey should be administered by an impartial party.