Exam 21: Critical Thinking About Research

Rolando realizes that whenever he studies for at least two hours immediately before a physics exam, he gets an A on the exam, but when he does not study immediately before an exam, he gets no higher than a C on the exam. He concludes that the time spent studying immediately before the exams is responsible for his improved grades. Rolando is

Which of the following examples would most likely be subject to survivor bias?

Which of the following examples would most likely be subject to selection bias?

Refer to the information provided in Table 21.3 below to answer the questions that follow. Table 21.3 The data in the table was used to estimate the following consumption function: C = 20 + 0.2Y. -Refer to Table 21.3. The error for point C is equal to

Refer to the information provided in Table 21.5 below to answer the questions that follow. Table 21.5 -Refer to Table 21.5. Which of the following consumption functions best fits the values in the table?

When computing p-values, population variation matters.

If people who own cats tend to have fewer mice on their property, we can say there is a negative correlation between owning cats and having mice on your property.

Suppose that a study is released stating that as people increase the number of times they brush their teeth each day, they increase the number of times they go to the gym each week. This is best described as an example of

Refer to the information provided in Scenario 21.5 below to answer the questions that follow. SCENARIO 21.5: The tiny nation of Bugaboo consists of two virtually identical islands, Achoo and Zoink, separated by the Strait of Dingo. The islands are similar in geography and population. The only telephone service on the islands is cellular, and the only cellular provider on the islands is the government-owned Bugaboo Communications Company, which charges a standardized rate of 20 Bugabucks per minute. Both islands add on an additional $5 Bugabucks-per-minute usage tax. As a way to increase revenue, the island governor of Zoink decided to increase the usage tax to $10 per minute, effective January 1, 2017. The average monthly cellphone usage per month is listed in the table below. Average Monthly Telephone Use per Resident (minutes) -Related to the Economics in Practice on p. 407: Refer to Scenario 21.5. Using the difference-in-differences method, what is the estimated effect of the increase in the usage tax on the average number of minutes used monthly per resident in Zoink?

Survivor bias

Refer to the information provided in Scenario 21.6 below to answer the questions that follow. SCENARIO 21.6: Following is information pertaining to four surveys: Survey 1: 50 pre-law students at Vanderbilt University are surveyed for a study to see if taking an LSAT preparation course was effective in improving their chance of being admitted to law school. Survey 2: 600 newly hired Houston-area elementary school teachers are surveyed for a study to determine how much salary they were willing to sacrifice to get a job teaching in a school with a high-quality reputation. Survey 3: 950 people are surveyed 6 months after buying a new car for a study to see how satisfied they are with their purchase. Survey 4: 75 people are surveyed in front of 5 different casinos on the Las Vegas Strip fo a study to determine the average daily gambling budget of a Las Vegas visitor. -Refer to Scenario 21.6. Of the four surveys, which is likely to be the most statistically significant?

Least squares estimates are the estimates that correspond to the smallest sum of the squared distances, or errors.

Survivor bias occurs when data used in a study reflects too broad a sample of the population.

Regression discontinuity is a method in which two groups are compared based on whether they were part of an initially specified random sample subjected to an experimental protocol.

The term "statistical significance" is commonly applied to a p-value of

Refer to the information provided in Scenario 21.5 below to answer the questions that follow. SCENARIO 21.5: The tiny nation of Bugaboo consists of two virtually identical islands, Achoo and Zoink, separated by the Strait of Dingo. The islands are similar in geography and population. The only telephone service on the islands is cellular, and the only cellular provider on the islands is the government-owned Bugaboo Communications Company, which charges a standardized rate of 20 Bugabucks per minute. Both islands add on an additional $5 Bugabucks-per-minute usage tax. As a way to increase revenue, the island governor of Zoink decided to increase the usage tax to $10 per minute, effective January 1, 2017. The average monthly cellphone usage per month is listed in the table below. Average Monthly Telephone Use per Resident (minutes) -Refer to Scenario 21.5. The total cost of telephone service for residents of Zoink in 2016 is ________ Bugabucks.

Refer to the information provided in Scenario 21.2 below to answer the questions that follow. SCENARIO 21.2: A survey of 1,000 people in Austin, Texas (population 900,000) found that those who have chosen to eat organic produce for at least the past 5 years have experienced fewer serious medical issues than those who have not elected to eat organic produce. Therefore, the conclusion was made that eating organic produce helps prevent people from experiencing serious medical problems. -Refer to Scenario 21.1. Which of the following statements pertaining to the scenario is the most accurate with respect to selection bias?

A research project is conducted by offering a randomly selected 75 of the 200 local dog owners a chance to have their dogs wear a new flea collar for three months to see if the collar reduces the incidence of fleas. 50 of the 75 randomly selected dog owners agree to the offer, and 25 of those drop out of the study before the end of the three months. Using the intention to treat method, the results from how many of the dogs that were not selected to be a part of the project should be included in the research project?

Assume a study indicates that attending an SAT preparation class improved average SAT scores by 200 points. If the null hypothesis is true and the p-value for the 200 point SAT score improvement is 0.015, then there is a ________ chance of improving your SAT score by 200 points.

Refer to the information provided in Scenario 21.6 below to answer the questions that follow. SCENARIO 21.6: Following is information pertaining to four surveys: Survey 1: 50 pre-law students at Vanderbilt University are surveyed for a study to see if taking an LSAT preparation course was effective in improving their chance of being admitted to law school. Survey 2: 600 newly hired Houston-area elementary school teachers are surveyed for a study to determine how much salary they were willing to sacrifice to get a job teaching in a school with a high-quality reputation. Survey 3: 950 people are surveyed 6 months after buying a new car for a study to see how satisfied they are with their purchase. Survey 4: 75 people are surveyed in front of 5 different casinos on the Las Vegas Strip fo a study to determine the average daily gambling budget of a Las Vegas visitor. -Refer to Scenario 21.6. Of the four surveys, which is likely to be the least statistically significant?