Exam 5: Statistical Reasoning

Identify which of these types of sampling is used: simple random, stratified, systematic, or convenience. -A pollster uses a computer to generate 500 random numbers, then interviews the voters corresponding to those numbers.

Make a bar graph to represent the data. -The following table shows the number of male infants born at Hospital X on New Year's Day (Jan. 1). Create a horizontal bar graph. No. of Male Year Infants Born on Jan 1 1990 12 1991 28 1992 20 1993 32 1994 20 1995 20

Identify which of these types of sampling is used: simple random, stratified, systematic, or convenience. -A market researcher selects 500 people from each of 10 cities.

Identify the variable as either qualitative or quantitative. -Waiting time at a bus stop (in minutes)

Use the graph to answer the question. - Identify the utility that makes up about 25% of the total bill in May.

Choose the best wording for the question in the study. -A recent newspaper article stated that Snazzy's is the most popular restaurant in the city. The city council decided to sponsor its own survey to determine the accuracy of the article. Which of the Following survey questions will give the most accurate results?

Answer the question. -Andrew creates a bar graph to show the increase in his company's sales. He wants to shov the milestones - years in which sales reached 10 million, 20 million, 30 million, 40 million, and 50 million dollars respectively. The data are shown in the table below: Year Sales (millions of dollars) 1975 10 1985 20 1993 30 1999 40 2003 50 In the graph, Andrew draws 5 equally spaced bars of heights 1 in, 2 in, 3 in, 4 in, and 5 in respectively. The height of each bar corresponds to the amount of sales. He labels each bar with the corresponding year (1975, 1985, 1993, 1999, 2003 respectively). Why is the graph misleading?

Solve the problem. -For the study described below, identify the sample statistic. 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.

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 smoking elevate blood pressure?

Identify which of these types of sampling is used: simple random, stratified, systematic, or convenience. -A sample consists of every 20th student who leaves the library.

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 the temperature has been rising over the past three months, the Dow Jones Industrial Average has also been rising.

Answer the question. -A researcher wishes to determine the percentage of voters in a town who favor stronger environmental laws. Which of the following would be the most representative sample?

Identify which of these types of sampling is used: simple random, stratified, systematic, or convenience. -A researcher interviews 19 work colleagues who work in his building.

Solve the problem. -For the study described below, identify the population. A manufacturer of light bulbs wants to determine the average lifetime of its 75-watt light bulbs. Among 120 randomly selected 75-watt light bulbs, the average lifetime was 1007 hours.

Make a scatter diagram for the data. -The table shows the unemployment rate and the median price of renting an apartment in nine cities. Unemployment Rate (Percent) Median Rent for Apartment (dollars) 2.1 950 4.6 760 6.4 1100 7.1 650 3.2 1070 7.2 620 5.0 840 2.4 1050 3.8 650 Plot unemployment rate on the horizontal axis and median rental price on the vertical axis.

Choose the best wording for the question in the study. -A recent magazine article determined that the Gemini is the most popular car on the road. A TV journalist decided to check the accuracy of the article by conducting a survey. Which of the Following survey questions will give the journalist the most accurate results?

Answer the question. -A parcel delivery service lowered its prices and finds that it has delivered twice as many parcels this year as it did last year. To illustrate this fact, the manager draws a pictogram as shown below. Each cube depicts a parcel. The side length of the "parcel" on the right is twice the side length of the "parcel" on the left. Why is this pictogram misleading? What visual impression is portrayed by the pictogram?

Answer as requested. -Which of the following is likely the result of some common underlying cause rather than a direct cause?

Use the guidelines to evaluate the study. Discuss flaws that you see in the study. -The principal of Laney High School interviews all the seniors at his school and asks them whether they have ever used drugs. The principal of Little Heath High School interviews all the seniors at her school and asks them whether they have ever used drugs. The results suggest that Laney has a lower rate of drug use. A researcher concludes that the counseling program available at Laney High School is effective in lowering drug use.

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. -People with higher incomes tend to live longer than those with lower incomes.