Exam 1: Collecting Data

In each situation, indicate whether the method of data collection is biased. -A professor asks her class of first year students if any of them consumed alcohol over the weekend.

Use the following to answer the questions below: The Admissions Office at a small university has developed a new 10-minute video about the university to send to prospective students. Before mass-producing the DVD, they would like to test whether it is more effective than the current video. Suppose that you have 12 high school student volunteers who have agreed to take part in an experiment. The explanatory variable to be studied is the type of video, with two levels OLD and NEW. -A group of students were asked to count the number of scars on both of their hands. The number of scars on their dominant hand was compared to the number of scars on their "off" hand. Is this an observational study or a randomized experiment?

Use the following to answer the questions below: A high school senior is collecting data on the colleges in which she is interested. Identify the variables as either categorical or quantitative. -Tuition: in thousands of dollars

Use the following to answer the questions below: Can people text just as quickly with their off hand as they do their dominant hand? Assume that you have 42 volunteers available to participate in your study, and that the response you will measure is the time it takes to type and send a text message. -Design a matched pairs experiment to investigate this question. Be specific about how randomization will be used in your experiment.

Sampling from a Population -A population includes all individuals or objects of interest.

Use the following to answer the questions below: A high school senior is collecting data on the colleges in which she is interested. Identify the variables as either categorical or quantitative. -Graduation Rate: as a percentage

Use the following to answer the questions below: State whether the data are best described as a population or a sample. -A professor wants to schedule a review session for an exam. He asks all students enrolled in the course their preferred time, and they all respond.

Use the following to answer the questions below: A recent study investigated the impact of psychological stress on men's judgments of female body size. The men were randomly assigned to one of two groups; one group was assigned to participate in a stressful task while the other group did not take part in the task. Then the men were asked to rate the attractiveness of female bodies varying in size from emaciated to obese. -Identify the explanatory variable in this experiment.

Use the following to answer the questions below: A realtor's website provides information on area homes that are for sale, including the following variables: List Price, School District, Size, Style. -Refer to the variables provided by the realtor. Identify a question we might ask about any one of these individual variables.

Use the following to answer the questions below: Identify whether each of the following scenarios describe a randomized comparative experiment or a matched pairs experiment. -To study the effect of classical music on concentration, 26 math majors were assigned at random into two groups. Subjects in one group listened to classical music while trying to solve a hard Sudoku puzzle, while the subjects in the other group solved the same puzzle in a silent room. The time it took each student to finish was recorded.

Use the following to answer the questions below: A tree enthusiast is interested in estimating the typical length of oak tree leaves. He chooses 30 leaves from the oak tree in his backyard. -What is the population in which the tree enthusiast is interested?

Use the following to answer the questions below: A group of researchers investigated the effect of media usage (whether or not subjects watch television or use the Internet) in the bedroom on "Tiredness" during the day (measured on a 50 point scale). -Identify the variables described and whether they are categorical or quantitative.

Use the following to answer the questions below: The Admissions Office at a small university has developed a new 10-minute video about the university to send to prospective students. Before mass-producing the DVD, they would like to test whether it is more effective than the current video. Suppose that you have 12 high school student volunteers who have agreed to take part in an experiment. The explanatory variable to be studied is the type of video, with two levels OLD and NEW. -Design a study that could be used in this situation. Give explicit instructions on what the 12 students should do, and be sure to indicate how randomization is used in the study.

Use the following to answer the questions below: A tree enthusiast is interested in estimating the typical length of oak tree leaves. He chooses 30 leaves from the oak tree in his backyard. -What is the sample in this situation?

Use the following to answer the questions below: Identify whether each of the following scenarios describe a randomized comparative experiment or a matched pairs experiment. -Is using meditation to relax and clear the mind a natural way to treat insomnia? Design an experiment to investigate this question. Assume that you have 20 individuals who suffer from insomnia available to participate in the study. At the end of two months, you will ask subjects to rate their sleep quality.

A company is interested in redesigning its website, and two possible designs are being considered. The company wants to get input in the form of ratings of the two designs. Design a matched pairs experiment to decide which design gets higher ratings. Fifty volunteers are available to participate.

Use the following to answer the questions below: A recent study investigated the impact of psychological stress on men's judgments of female body size. The men were randomly assigned to one of two groups; one group was assigned to participate in a stressful task while the other group did not take part in the task. Then the men were asked to rate the attractiveness of female bodies varying in size from emaciated to obese. -Is this an experiment or an observational study?

Use the following to answer the questions below: A university's Admissions staff sends one of four different representatives to work at college fairs. A study was conducted to evaluate the relative effectiveness of the four representatives. For each college fair over the course of the year, the number of inquiries from students, the type of fair (large or small), the representative who worked at that fair, and the percent of inquiries that resulted in applications were recorded. It was found that one of the representatives was far more effective at getting lots of inquiries. -Can we conclude that sending the most effective representative to more college fairs will increase the number of inquiries from those college fairs?

Use the following to answer the questions below: A high school senior is collecting data on the colleges in which she is interested. Identify the variables as either categorical or quantitative. -Enrollment: the number of students enrolled at the college

Use the following to answer the questions below: Identify whether each of the following scenarios describe a randomized comparative experiment or a matched pairs experiment. -To study the impact of texting while driving, researchers have students drive around an obstacle course twice, once while texting and once without texting (the order of which was randomized). Their score for each turn is the number of obstacles they successfully maneuvered around.