Chapter One Review
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.
1.) Manipulation: The research manipulates one varble by changing its value from one level to another. A second variable is observed to determine whether the manipulation causes changes to occur. 2.) Control: the researcher must exercise control over the research situation to ensure that other, extraneous variables do not influence the relationship being examined.
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.
1.) Social security number is Nominal variable. Annual income is Ratio variable. Number of dependents is Ratio variable. 2.) Social security number is discrete variable. Annual income is continuous variable. Number of dependents is discrete variable.
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.
A correlational study has only one group of individuals and measures two (or more) different variables for each individual. Other research methods evaluating relationships between variables compare two (or more) different groups of scores.
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.
A.)
For the following set of scores, find the value of each expression: X 3 5 4 2 1 A.) nE(X-1) B.) EX-3^2 C.) E(X-2) / n D.) E(X-4)^2
A.) B.) C.) D.)
For the following set of scores, find the value of each expression: X 6 1 4 5 2 A.) EX^2 B.) (EX)^2 C.) E(X-3) D.) E(X-3)^2
A.) B.) C.) D.)
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.
A.) (EX)^2 B.) EX^2 C.) E(X-2) D.) E(X-1)^2
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?
A.) An ordinal scale provides information about the direction of difference (greater or less) between two measurements. B.) An interval scale provides information about the magnitude of the difference between two measurements. C.)A ratio scale provides information about the ratio of two measurements, which allow comparisons such as "twice as much."
For the following set of scores, find the value of each expression: X −1 −3 6 −4 0 A.) E(X-4)^2 B.) (EX)^2 C.) EX^2 D.) E(X+3)
A.) E(X-4)^2=158 B.) E(X)^2=(-2)^2=4 C.) EX^2=62 D.) E(X+3)=13
For the following scores, find the value of each expression: X 4 2 6 3 A.) EX B.) (EX)^2 C.) EX-3 D.) E(X-3)
A.) EX=15 B.) . (EX)^2=(15)^2=225. Note that if you answered 65, you were incorrect because you squared the scores before summing them. C.)EX-3=15-3=12. Note that if your answer was 3, you were incorrect because you subtracted 3 from each score before summing. D.). E(X-3)=(4-3)+(2-3)+(6-3)+(3-3)=(-1)+(3)+(0)=3. Note that if your answer was 12, you were incorrect because you summed the scores before subtracting 3.
Two scores, X and Y, are recorded for each of n=5 participants. For these scores, find the value of each expression. Participant x y A 3 1 B 1 5 C -2 2 D -4 2 E 2 4 A.) EX B.) EY C.) E(X+Y) D.) EXY
A.) EX=3+1-2-4+2=0 B.) EY= 1+5+2+2+4= 14 C.) E(X+4)= ( 3+1)+(1+5)+(-2=2)=(-4+2)+(2+6)=4+6 to -2+6 E(X+4)=14 D.) EXY= 3(1)+1(5)+(-2)(2)+(-6)(2)+2(4) =3+5-4-8+8 EXY=4
For the following set of scores, find the value of each expression: Participant X Y A 6 1 B 3 0 C 0 2 D -1 4 A.) EXY B.) EXEY C.) EY D.) n=?
A.) EXY=2 B.) EXEY= 56 C.) EY= 7 D.) n=4
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.) Loneliness is a continuous variable. If it is measured with ratings of 1 to 4, it may appear to be discrete but it could be measured with a 1 to 40 rating, which means that each category could be further divided. The UCLA Loneliness Scale is an interval scale of measurement because a value of zero does not represent a complete absence of loneliness. B.) n = 86 C.) This is an experimental study because participants were randomly assigned to groups. D.) The group that was instructed to post more status updates is an experimental group.
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 _____.
A.) Statistic ( or descriptive statistic) B.) Parameter
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?
A.) The average score in the afternoon was 80 and the average score in the morning was 76, so you might be tempted to think that there is some real advantage for testing in the afternoon. However, the difference between means could be due to random chance alone—sampling error. Based on the descriptive statistics given in this sample, we just don't know whether an advantage exists or not. B.) Inferential statistics
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?
A.) The dependent variable is the number of correct answers on the test, which is a measure of knowledge of the material. B.) Knowledge is a continuous variable. If it is measured with a 10-question test, it may appear to be discrete but it could be measured with a 100-question test, which means that each category can be further divided. C.) Ratio scale. Zero is absolute, which means a complete absence of correct answers.
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?
A.) The independent variable is whether or not the motivational signs were posted where as the dependent variable is an amount of use of the stairs. B.) the data is having only two options such as posting versus not posting. the data is measured on a nominal scale.
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 ______.
A.) The population consists of all high school students in the United States. B.) The sample is the group of 100 students who were measured in the study. C.) The average number is a statistic. Notice that you might be more specific and say "descriptive" statistic. Inferential statistic or parameter would be incorrect because the calculated average describes only the data measured in the sample.
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.
A.) This study used the experimental method because participants were randomly assigned to groups that received different instructions B.) The independent variable was the instructions received by participants (that is, being told that their group waited and the other didn't versus being told that their group didn't wait and the other group waited). The dependent variable was whether or not children chose to wait for a larger reward.
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. E.) 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?
A.) independent variable is subject dependent value is Flavor B.) the scale of measurement of the dependent variable is Ounce C.) the dependent variable is continuous
For the following set of scores, find the value of each expression: Participant X Y A 3 2 B 1 6 C 5 0 D 2 5 E 0 6 A.) nEX^2 B.) (EY)^2 C.) EXY D.) EXEY
A.) nEX^2=195 B.) (EY)^2=361 C.) EXY=22 D.) EXEY=209
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 _______.
A.)The population consists of all college students in the United States. B.)The sample consists of the 100 students who participated in the study. C.)The group that received decaffeinated coffee is in a control condition (that is, no caffeine). D.)The group that received the caffeinated coffee is in an experimental condition. E.)The sample contains 100 participants (50 in each group). The population is either infinitely large or too large for it to be practical to measure all members. If you said that the population consisted of 100 students, you might have mistakenly thought that the population consisted of everyone in the study. F.)The average calculated after the memory test is a "statistic" or, more specifically, "descriptive statistic." "Inferential statistic" or "parameter" would be incorrect because the average describes only the data in the sample.
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.
A.)This is not an experiment because no independent variable is manipulated and participants are not randomly assigned to groups that receive different amounts of milkfat. B.)It is possible that participants in the reduced milkfat (skim or 1% milk) group (that is, children who regularly drank reduced-fat milk) also tended to be more sedentary. C.) Possibility 1: A researcher could randomly assign participants to groups that receive different amounts of milkfat. Possibility 2: A researcher could assign participants to two groups that receive different amounts of milkfat, holding constant characteristics like the amount of physical activity by participants in each group. Possibility 3: A researcher could assign participants to two groups that receive different amounts of milkfat, matching the two groups in the amount of physical activity.
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.
Age: ratio scale and continuous. Although people usually report whole-number years, the variable is the amount of time and time is infinitely divisible. Income: ratio scale and discrete. Income is determined by units of currency. For U.S. dollars, the smallest unit is the penny and there are no intermediate values between 1 cent and 2 cents. Dependents: ratio scale and discrete. Family size consists of whole-number categories with no intermediate values. Social Security: nominal scale and discrete. Social security numbers are essentially names that are coded as 9-digit numbers. There are no intermediate values between two consecutive social security numbers.
Define the terms population and sample, and explain the role of each in a research study.
In a research study, the researcher aims to study a certain phenomenon on a group, this group consist of all the persons belonging to the population. As it is not possible to study all the members of that group, the researcher must take in some people who are part of that group. SAMPLE is the participants who are part of a population, they represent the population. If a population is diverse in nature, then the sample should also be diverse and accurately represent the population. For example, a correlational study is done to find the association between physical exercise and it's effect on hypertension patients. Here, the population is all the hypertension patients, so to accurately represent the population, a sample of hypertension patients is taken from a hospital by settings some exclusion criteria such as co-morbidity, as taking in co-morbid patients will not represent the hypertension population.
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?
Lower Limit of the height = 69.5 Upper Limit of the height = 70.49... There could be multiple reasons for the fact that it's highly unlikely that the height is 70 inches. Below are some of them 1. Measurement Error: There's always the potential for measurement error. 2. Random Error: The value of the measurement could change randomly which is beyond the control of the observer.
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.
Nonexperimental study Researcher observing the two groups of students who are participated in the survey. There is no evidence of any manipulations in the variable of the study. The given study is about the gaming habit and other behavior of 8th -9th grade students; study is non- experimental study
Statistical methods are classified into two major categories: descriptive and inferential. Describe the general purpose for the statistical methods in each category.
Statistical methods are classified into two major categories: 1. Descriptive statistics 2. Inferential statistics Descriptive statistics: are statistical procedures used to summarize, organize and simplify data. Descriptive statistics are techniques that take raw scores and organize or summarize them in a form that is more manageable. Often the scores are organized in a table or graph so that it is possible to see the entire set of scores. Inferential statistics: consist of techniques that allow us to study samples and then make generalizations about the populations from which thy were selected. It is usually not possible to measure every value in the population. Because population are typically very large, a sample is selects to represent the population. By analyze the result from the sample, to make a general statement about population.
Define the terms statistic and parameter and explain how these terms are related to the concept of sampling error.
The term statistics refer numerical value that describe sample and parameter is numerical value that describe population. The statistic provide limited information about parameter refers sampling error.
Your friend measures the temperature of her coffee to be 70 Celsius. Your friend also notices that the temperature outside is 35 Celsius. Why is it incorrect to say that the coffee is twice as warm as the temperature outside?
To make comparisons like the one provided in the question, we need an absolute scale of temperature. Celsius scale is not an absolute scale, but an offset scale. When we convert the temperatures into Kelvin, and thus moving it upon an absolute scale, we then and there realise that 70 degree Celsius is actually 70+273=343 K and 35 degree Celsius is actually 35+273=308 K (of course you have to keeo in mind that 0 degree celsius equals 273K). So, actally, the coffee is around 11.36% warmer in comparison to the outside temperature.
