Exam 5: Statistical Reasoning

Answer the question. -Which of the following describes a study in which neither the participants nor the experimenters know which participants are in the control group?

Use the graph to answer the question. - In what quarter was the revenue the least for 2000?

The graph below shows estimated world population for the period 4000 BC = 2000 AD. Note that the logarithm of the world population and not actual population is plotted on the vertical axis. This means, for example, that when the graph reaches 7 on the vertical scale, world population is $10 ^ { 7 }$ and when the graph reaches 9 on the vertical scale, world population is $10 ^ { 9 }$ Use the graph to answer the question. -How does world population in the year 2000 AD compare with world population in the year 4000 BC?

Describe how you would apply the five basic steps of a statistical study to the given issue. -You want to know the average volume of juice in your company's 500 mL bottles of orange juice.

Provide an appropriate response. -Explain in your own words the difference between a bar graph and a histogram. Give an example of data for which you might use a histogram and an example of data for which you might use a bar graph.

Use the guidelines to evaluate the study. Discuss flaws that you see in the study. -A researcher randomly selects 300 adults from the city of Kentwood by using a random number generator and a list of residents of the town. She calls the people in the sample and asks the following question: "Do you agree that more of the city's budget should be spent on social services for the poor? " She announces that 54% of the people in Kentwood feel that more of the city's budget should be spent on social services for the poor.

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? -What percentage of the population reads a newspaper on a regular basis?

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 total value of Danny's investments the least?

Use the guidelines to evaluate the study. From the information given, what is the biggest flaw in the study? -An educational researcher wishes to compare the effectiveness of two different math textbooks. She has the tenth graders at one school use the first book for one year and the tenth graders at another School use the second textbook for one year. At the end of the year, she gives the same math test to Both classes and compares the results.

Construct a pie chart representing the given data set. - Computers per household Number of households 0 72 1 128 2 76 3 36

Use the guidelines to evaluate the study. Discuss flaws that you see in the study. -An acupuncturist notes that after a month of acupuncture 80% of her patients who had been suffering from depression are feeling better. The acupuncturist determines the level of depression by interviewing the patients at the beginning of the month and at the end of the month. She concludes that acupuncture has an 80% success rate in relieving depression.

Use the guidelines to evaluate the study. Discuss flaws that you see in the study. -The host of a conservative talk show asked his listeners to respond to the following question: "Do you think that environmental laws which restrict growth should be weakened?" Twenty people responded, and the next day the talk show host announced that the results of his survey suggested that 76% of Americans feel that environmental laws should be weakened.

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 highest?

Solve the problem. -A researcher finds a negative correlation between blood pressure and the number of vacations that people take. Can you conclude that taking vacations lowers blood pressure? Propose other explanations for the correlation. Suggest some ways that the researcher could go about establishing causality. Refer to the six guidelines for establishing causality.

State whether the scatter diagram shows strong positive correlation, weak positive correlation, strong negativecorrelation, weak negative correlation, or no correlation. -

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 caffeine cause birth defects?

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

Describe how you would apply the five basic steps of a statistical study to the given issue. -You want to know the average amount paid in rent by tenants of the city of Hazelwood.

Identify which of these types of sampling is used: simple random, stratified, systematic, or convenience. -A market researcher randomly selects 500 drivers under 30 years of age and 500 drivers over 30 years of age.

Solve the problem. -For the study described below, identify the sample. A bank manager wants to know the average amount of time customers of his bank have to wait in Line. 300 customers were polled and asked their average wait time at the bank. 27 of the 300 were Extremely dissatisfied with the amount of time they had had to wait in line in recent months.