Exam 5: Statistical Reasoning

Answer the question. -Which of the following describes the bias that occurs when researchers select their sample in such a way that it is unlikely to be representative of the population?

Determine whether the study involves selection bias, participation bias, both selection bias and participation bias, orneither. -A researcher published this survey result: "74% of people would be willing to spend 10 percent more for energy from a non-polluting source". The survey question was announced on a national Radio show and 1200 listeners responded by calling in.

Provide an appropriate response. -Suppose that you want to construct a pie chart to represent the following data. Blood Type Frequency O 90 A 84 B 18 AB 8 Explain how you would calculate the angle for the pie-shaped piece corresponding to the blood type O.

Choose the best wording for the question in the study. -A researcher wants to determine the level of support for the war. Which of the following questions would produce the most accurate results?

State whether you think that the variables have strong positive correlation, weak positive correlation, strong negativecorrelation, weak negative correlation, or no correlation. -Number of appliances sold and revenue of appliance store

Create a graphical display for the data given. You may choose any graphic type that you feel is appropriate. Write a fewsentences explaining why you chose this type of display and a few sentences describing any interesting patterns in thedata. -The table below shows the number of AIDS diagnoses for the United Kingdom by year. Year of diagnosis Male Female 1993 1549 237 1994 1628 225 1995 1487 282 1996 1164 270 1997 857 216 1998 592 192 1999 556 189 2000 572 236

Construct a pie chart representing the given data set. - Favorite Beverage Number of responses Cola 170 Juice 105 Milk 115 Tea 155 Water 75

The stack plot below shows the value of each of Danny's investments. The stack plot contains three regions. Theuppermost unshaded region represents the value of Danny's investment in individual stocks. The center shaded regionrepresents the value of Danny's investment in mutual funds and the bottom region in black represents the value ofDanny's investment in a CD. The thickness of a region at a particular time tells you its value at that time. Use the graph to answer the question. -In which year was the value of Danny's investment in individual stocks the least?

A sample statistic and margin of error are given. Find the confidence interval likely to contain the population parameterof interest and answer the question. -A poll conducted the day before the student-body presidential election at a midwestern university showed that 53.0 percent favored Mario, the rest favoring Yin Ling. The margin of error was 5.0 Percentage points. Should Yin Ling have conceded the election?

A statement is made about correlation. State whether the correlation is positive or negative and whether the correlation ismost likely due to coincidence, a common underlying cause, or a direct cause. -Towns with a lot of churches had a lot of homicides last year. Towns with fewer churches had fewer homicides.

Answer the question. -The strengths of the last 5 major earthquakes to hit California have differed by factors of 10. If you were to display data describing the strengths of these earthquakes what could you use to make the Graph more readable?

A sample statistic and margin of error are given. Find the confidence interval likely to contain the population parameterof interest and answer the question. -Following the Republican National Convention, a poll of voters in a Central Illinois community showed that 58.1% would choose the Republican ticket to win over the Democrat ticket no matter Whom the Democrats chose for vice-president. The margin of error was 4.2 percentage points. Should the Democrats expect to lose Central Illinois?

Solve the problem. -A researcher suspects that pesticides in foods cause cancer. Suggest some ways that she could go about establishing causality. Refer to the six guidelines for establishing causality. For each guideline suggest some research that should be pursued. Discuss any challenges that the researcher would face in establishing causality.

Answer the question. -Which of the following quantities of interest would be the most difficult to define?

Choose the best wording for the question in the study. -If you wanted to determine if your customers are satisfied with the selection in your store, which of the following survey questions would give you the most accurate results?

Answer the question. -Which of the following describes the process by which scientists examine each others' research?

In order to answer the given question, which of the following types of study would be the most appropriate: anexperiment without blinding, an experiment with single blinding, an experiment with double blinding, an observationalstudy, or a case-control study? -Does the new medication relieve depression?

Answer as requested. -Which of the following best describes our level of confidence in causality when we have discovered a correlation but cannot yet determine whether the correlation implies causality?

Answer the question. -Double blinding is used in an experiment to avoid which of the following problems?

Use the graph to answer the question. - Identify the utility that accounts for over half the total bill in two months.