Exam 1: Collecting Data

Use the following The USStates dataset, used throughout the textbook, contains information on the 50 U.S. states from 2008. A small segment from the dataset is displayed in the following table. -What variable was used to determine that 43.4% of Connecticut state residents have a college degree? Is it categorical or quantitative?

Use the following 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.

A sample of college age students shows an interesting association between hair length (in inches) and height (also in inches). On average, shorter students tend to have longer hair. What is a possible confounding variable that would help explain this relationship? Explain briefly.

Use the following 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 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 A realtor's website provides information on area homes that are for sale. Identify each of the variables as either categorical or quantitative. -Size: in square feet

Use the following The USStates dataset, used throughout the textbook, contains information on the 50 U.S. states from 2008. A small segment from the dataset is displayed in the following table. -What variable from this dataset is displayed? Is it categorical or quantitative?

Use the following A 2012 study investigated the impact of psychological stress on men's judgements 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. -Briefly explain why this is an experiment and not an observational study.

Use the following A high school senior is collecting data on the colleges in which she is interested. Identify the variables as either categorical or quantitative. -Student-Faculty Ratio: the number of students divided by the number of faculty

A population is a subset of the sample.

Refer to the variables collected by the high school senior looking at colleges. Identify a question that we might ask about relationships between any two (or more) of these variables.

Use the following A 2012 study investigated the impact of psychological stress on men's judgements 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. -What are the cases in this study?

On their website, the makers of Cold-EEZE lozenges provide links to studies done to demonstrate the effectiveness of their product at shortening the duration of the common cold. One study, published in the Annals of Internal Medicine, is described as a "randomized, double-blind, placebo-controlled" study. Briefly explain what the phrase "randomized, double-blind, placebo-controlled" means.

Use the following 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. -What are the cases in this study?

Use the following 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.

A population includes all individuals or objects of interest.

Use the following A 2012 study investigated the impact of psychological stress on men's judgements 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 a control group used in this experiment? If so, which group is the control group?

Use the following In each situation, indicate whether the method of data collection is biased. If it is, briefly explain why. -A professor is considering a new textbook for her introductory statistics class. She wants to choose a book that emphasizes graphing data. A book that she is considering has 530 pages. To estimate the proportion of pages in the book that have displays of data, she randomly generates 20 numbers between 1 and 530. She then records whether or not each selected page contains displays of data.

Use the following State whether the data are best described as a population or a sample. -The makers of M&M's state that when they package their candies they thoroughly mix the colored candies together and randomly put them into packages. A student purchases a bag of Milk Chocolate M&M's from the vending machine.

When purchasing some foods, like Jello, at the grocery store, the color of the product typically "matches" the taste. For example, lemon-flavored Jello is yellow, cherry-flavored Jello is red, orange-flavored Jello is orange, and grape-flavored Jello is purple. But, does the color of our food impact the taste that we perceive? Suppose you want to design an experiment to address this question. Note that you can easily make your own "Jello" with simple ingredients that include unflavored gelatin, flavored extracts, and food coloring. Assume that the 30 college students are willing to participate in your study and the response variable is the number of flavors correctly identified. How would you design a randomized comparative experiment with two groups, each getting a different treatment? Be sure to explain how randomization is used.