Exam 5: Statistical Reasoning

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

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? -In which of these four soil types will the plants grow fastest?

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

Answer the question. -The mayor of one city has been conducting an anti-smoking campaign in high schools. Each year local government researchers estimate the number of teenagers in the city who smoke. The number of smokers has declined steadily in each of the past five years. The mayor's office constructs a bar graph showing the number of teenage smokers in each of the past five years. If the mayor wished to exaggerate the success of his anti-smoking campaign, would it be to his advantage to truncate the bar graph? Explain your thinking.

Construct the specified histogram. -30 police detectives were asked how many days they had taken off in the previous year. The results are summarized in the frequency table below . Days off Frequency 0-1 10 2-3 1 4-5 7 6-7 7 8-9 1 10-11 4 Construct a histogram.

Use the graph to answer the question. -The time series line chart below shows the price of a volatile stock from January to December of the same year. Describe the overall trend in the price during that period.

Construct the specified histogram. -24 high school students were asked how many hours they had spent preparing for a test. The times (in hours) are as follows: $6,5,6,4,6,6,9,7,6,3,8,5,5,8,6,5,8,6,5,7,5,8,7,4$ Use 2 -point bins ( 3 to 4,5 to 6 , etc) to construct the relative frequency histogram.

Use the guidelines to evaluate the study. From the information given, what is the biggest flaw in the study? -A film critic is interested in knowing which is the most popular film of the year amongst Americans. To answer this question, he conducts a telephone poll in the New York metropolitan Area and asks each person to name their favorite film of the year.

Provide an appropriate response. -Consider the frequency table below which has single values as classes: Value Frequency 10 1 11 3 12 7 13 18 14 10 15 4 16 2 17 7 18 16 19 10 20 6 21 2 Construct a new frequency table for this data with 4 classes. Now construct another frequency table for this data with 6 classes. Suppose that you construct a histogram corresponding to the original data and histograms corresponding to each of the new frequency tables. Describe the shapes of the three histograms. Does the histogram with six classes capture the distribution of the data? Does the histogram with four classes capture the distribution of the data?

Construct a pie chart representing the given data set. - Favorite Food Number of Responses Chinese 184 Indian 120 Mexican 192 Thai 144

Make a bar graph to represent the data. -The table lists the winners of the Wimbledon women's singles title for the years 1976-1995. Construct a vertical bar graph for the given relative frequencies. Winner Frequency Relative frequency C. Evert 2 0.10 V. Wade 1 0.05 M. Navratilova 9 0.45 C. Martinez 1 0.05 S. Graf 6 0.30 E. Goolagong 1 0.05

Write the word or phrase that best completes each statement or answers the question.Solve the problem. -A researcher finds a positive correlation between the number of vaccinations and the incidence of autism. Can you conclude that vaccinations can cause autism? Suggest some ways that the researcher could go about establishing causality. Refer to the six guidelines for establishing causality.

Identify the variable as either qualitative or quantitative. -The professions of adults

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. -As Thomas's income rose over the last 20 years so has his stress level.

Answer the question. -In a graph that displays the annual percent increase in the price of grain, what does it mean if the graphs falls over a certain period?

Solve the problem. -For the study described below, identify the population parameter. 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 People were extremely dissatisfied with the amount of time they had had to wait in line in recent Months.

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

The graph below shows the approximate annual percentage growth rate in world population for the years 1960 through 2010. Data is estimated by the UN Census Bureau. Use the graph to answer the question. -In which year(s)during the period 1960-2010 is world population growing at the fastest rate?

The graph below shows the approximate annual percentage growth rate in world population for the years 1960 through 2010. Data is estimated by the UN Census Bureau. Use the graph to answer the question. -How does world population in 1978 compare to world population in 1977?

Identify the variable as either qualitative or quantitative. -The speed of a car in miles per hour