?A research study comparing alcohol use for college students in the United States and

A researcher is interested in the texting habits of high school students in the United States. The researcher selects a group of 100 students, measures the number of text messages that each individual sends each day, and calculates the average number for the group. a. Identify the population for this study. b. Identify the sample for this study. c. The average number that the researcher calculated is an example of a _____.

Define the terms population and sample, and explain the role of each in a research study.

A researcher conducted an experiment on the effect of caffeine on memory in college students in the United States. The researcher randomly assigned each of 100 students to one of two groups. One group received caffeinated coffee followed by a memory test. The second group received decaffeinated coffee followed by a memory test. The researcher calculated the average number of items correctly recalled in each group. a. What is the population? b. What is the sample? c. The group that received decaffeinated coffee is a(n) __________. d. The group that received caffeinated coffee is a(n) __________. e. The sample contains participants. The population contains ____________ . f. The averages calculated after the memory test is a ___________.

Statistical methods are classified into two major categories: descriptive and inferential. Describe the general purpose for the statistical methods in each category.

We know that the average IQ of everyone in the United States is 100. We randomly select 10 people and observe that their average IQ is 105. a. The value of 105 is a ________ . b. The value of 100 is a ________ .

Define the terms statistic and parameter and explain how these terms are related to the concept of sampling error.

A professor is interested in whether student performance on exams is better in the afternoon than in the morning. One sample of students was randomly assigned to receive the exam in the morning and another sample was randomly assigned to receive the exam in the afternoon. The following data were collected: The average score for morning students was 76 and the average score for afternoon students was 80. The professor concludes that the afternoon is the best time for students to complete the exam and that the difference in average scores reveals an important difference between afternoon and morning classes in college. a. Describe how sampling error could account for this difference. b. What type of statistic would the professor use to determine if the difference in exam averages between the samples provides convincing evidence of a difference between the time of day, or if the difference is just chance?

Explain why honesty is a hypothetical construct instead of a concrete variable. Describe how honesty might be measured and defined using an operational definition.

A tax form asks people to identify their age, annual income, number of dependents, and social security number. For each of these four variables, identify the scale of measurement that probably is used and identify whether the variable is continuous or discrete.

In your most recent checkup, your physician listed that your height is 70 inches, rounded to the nearest whole inch. Why is it unlikely that your height is exactly 70 inches? What are the upper and lower real limits of your height?

Four scales of measurement were introduced in this chapter, from simple classification on a nominal scale to the more informative measurements from a ratio scale. a. What additional information is obtained from measurements on an ordinal scale compared to measurements on a nominal scale? b. What additional information is obtained from measurements on an interval scale compared to measurements on an ordinal scale? c. What additional information is obtained from measurements on a ratio scale compared to measurements on an interval scale?

Your friend measures the temperature of her coffee to be \(70^{\circ}\) Celsius. Your friend also notices that the temperature outside is \(35^{\circ}\) Celsius. Why is it incorrect to say that the coffee is twice as warm as the temperature outside?

Describe the data for a correlational research study and explain how these data are different from the data obtained in experimental and nonexperimental studies, which also evaluate relationships between two variables.

Describe how the goal of an experimental research study is different from the goal for nonexperimental or correlational research. Identify the two elements that are necessary for an experiment to achieve its goal.

The results of a recent study showed that children who routinely drank reduced fat milk (1% or skim) were more likely to be overweight or obese at ages 2 and 4 compared to children who drank whole or 2% milk (Scharf, Demmer, & DeBoer, 2013). a. Is this an example of an experimental or a nonexperimental study? b. Explain how individual differences could provide an alternative explanation for the difference in weight between the groups. c. Create a research study that would be able to differentiate among those interpretations of the results.

Gentile, Lynch, Linder, and Walsh (2004) surveyed more than 600 eighth- and ninth-grade students regarding their gaming habits and other behaviors. Their results showed that the adolescents who experienced more video game violence were also more hostile and had more frequent arguments with teachers. Is this an experimental or a nonexperimental study? Explain your answer.

Deters and Mehl (2013) studied the effect of Facebook status updates on feelings of loneliness. Eighty-six participants were randomly assigned to two groups. One group was instructed to post more social media status updates and the other group was not. The researchers measured participants’ loneliness using the UCLA Loneliness Scale, which consists of 10 items that ask participants to rate from 1 (“Never feel this way”) to 4 (“I often feel this way”) how often they experience specific feelings of loneliness (for example, “How often do you feel shut out and excluded by others?”). Participants who were instructed to post status updates had lower loneliness scores. a. For the measurement in this study, identify whether it is discrete or continuous and list the scale of measurement. b. What is the value of n? c. Is this an experimental or nonexperimental study? Explain. d. The group that was instructed to post more status updates is a(n) ___________ .

A research study comparing alcohol use for college students in the United States and Canada reports that more Canadian students drink but American students drink more (Kuo, Adlaf, Lee, Gliksman, Demers, & Wechsler, 2002). Is this study an example of an experiment? Explain why or why not.

Ackerman and Goldsmith (2011) compared learning performance for students who studied material printed on paper versus students who studied the same material presented on a computer screen. All students were then given a test on the material and the researchers recorded the number of correct answers. a. Identify the dependent variable for this study. b. Is the dependent variable discrete or continuous? c. What scale of measurement (nominal, ordinal, interval, or ratio) is used to measure the dependent variable?

Dwyer, Figuerooa, Gasalla, and Lopez (2018) showed that learning of flavor preferences depends on the relative value of the reward with which a flavor is paired. In their experiment, rats received pairings of a cherry flavor with 8% sucrose solution after exposure to 32% sucrose solution, which made the 8% solution a relatively low value. On other trials, a grape flavor was paired with 8% sucrose solution after exposure to a 2% sucrose solution, which made the 8% solution a relatively high value. Thus, cherry was paired with a relatively low-value reward and grape was paired with a relatively high-value reward. They observed that rats consumed more in ounces of cherry flavor than grape flavor at a later test. a. Identify the independent and dependent variables for this study. b. What scale of measurement is the dependent variable? c. Is the dependent variable discrete or continuous? d. Imagine that the researcher reported that subject number 4 consumed 2.5 ounces of cherry-flavored water. Consumption of the solution was rounded to the nearest tenth of an ounce. What are the lower and upper real limits of subject 4’s score?

Doebel and Munakata (2018) discovered that delay of gratification by children is influenced by social context. All children were told that they were in the “green group” and were placed in a room with a single marshmallow. Participants were told that they could either eat the single marshmallow now or wait for the experimenter to return with two marshmallows. Before choosing between one marshmallow now or two later, children were randomly assigned to one of two conditions. They were told that either (1) other children in the green group waited and kids in the orange group didn’t wait or (2) other children in the green group didn’t wait and kids in the orange group waited. Children were more likely to choose to wait after being told that other members of their group waited. a. Did this study use experimental or nonexperimental methods? b. Identify the variables in this study.

Ford and Torok (2008) found that motivational signs were effective in increasing physical activity on a college campus. Signs such as “Step up to a healthier lifestyle” and “An average person burns 10 calories a minute walking up the stairs” were posted by the elevators and stairs in a college building. Students and faculty increased their use of the stairs during times that the signs were posted compared to times when there were no signs. a. Identify the independent and dependent variables for this study. b. What scale of measurement is used for the independent variable?

For the following scores, find the value of each expression: a. \(\sum X\) b. \((\Sigma X)^{2}\) c. \(\Sigma X-3\) d. \(\Sigma(X-3)\)

For the following set of scores, find the value of each expression: a. \(n \Sigma(X-1)\) b. \(\sum X-3^{2}\) c. \(\frac{\Sigma(X-2)}{n}\) d. \(\Sigma(X-4)^{2}\)

For the following set of scores, find the value of each expression: a. \(\sum(X-4)^{2}\) b. \(\left(\sum X\right)^{2}\) c. \(\Sigma X^{2}\) d. \(\Sigma(X+3)\)

Two scores, X and Y are recorded for each of n = 5 participants. For these scores, find the value of each expression. a. \(\Sigma X\) b. \(\Sigma Y\) c. \(\Sigma(X+Y)\) d. \(\Sigma X Y\)

For the following set of scores, find the value of each expression: a. \(\Sigma X Y\) b. \(\sum X \Sigma Y\) c. \(\sum Y\) d. \(n=?\)

Use summation notation to express the following calculations. a. Multiply scores X and Y and then add each product. b. Sum the scores X and sum the scores Y and then multiply the sums. c. Subtract X from Y and sum the differences. d. Sum the X scores.

Use summation notation to express each of the following calculations: a. Add the scores and then square the sum. b. Square each score and then add the squared values. c. Subtract 2 points from each score and then add the resulting values. d. Subtract 1 point from each score and square the resulting values. Then add the squared values.

For the following set of scores, find the value of each expression: a. \(\Sigma X^{2}\) b. \(\left(\sum X\right)^{2}\) c. \(\Sigma(X-3)\) d. \(\sum(X-3)^{2}\)

For the following set of scores, find the value of each expression: a. \(n \sum X^{2}\) b. \(\left(\sum Y\right)^{2}\) c. \(\Sigma X Y\) d. \(\Sigma X \Sigma Y\)

For the following set of scores, find the value of each expression: a. \(n \sum X^{2}\) b. \(\left(\sum Y\right)^{2}\) c. \(\Sigma X Y\) d. \(\Sigma X \Sigma Y\)