PSY213 Chap 1
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?
70 degrees Celsius is not twice as warm as 35 degrees Celsius because temperature in Celsius is an interval scale (and not a ratio scale). Because zero degrees Celsius does not represent a complete absence of heat (i.e., Celsius uses an arbitrary zero), it is incorrect to say that 70 degrees Celsius is twice as warm as 35 degrees Celsius.
Deters and Mehl studied the effect of FB status updates on feelings of loneliness. 86 participants were randomly assigned to 2 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?
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
Ackerman 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=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 signs were posted and the dependent variable is how much the stairs were used. b. Posted versus not posted is measured on a nominal scale.
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 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.
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.
1. An operational definition is used to ---------a hypothetical construct. a. define b. measure c. measure and define d. None of the other choices is correct.
c. measure and define
Researchers are interested in how robins in New York State care for their newly hatched chicks. The team measures how many times per day the adults visit their nests to feed their young. The entire group of robins in the state is an example of a . a. sample b. statistic c. population d. parameter
c. population
The SAT is standardized so that the population average score on the verbal test is 500 each year. In a sample of 100 graduating seniors who have taken the verbal SAT, what value would you expect to obtain for their average verbal SAT score? a. 500 b. Greater than 500 c. Less than 500 d. Around 500 but probably not equal to 500
d. Around 500 but probably not equal to 500
Stephens, Atkins, and Kingston found that participants were able to tolerate more pain when they shouted their favorite swear words(悪い言葉) over and over than when they shouted neutral words. For this study, what is the independent variable? a. The amount of pain tolerated b. The participants who shouted swear words c. The participants who shouted neutral words d. The kind of word shouted by the participants
d. The kind of word shouted by the participants
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. e. The sample contains--------- participants. The population contains -----------.
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.
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. f. The averages calculated after the memory test is a ----------.
f. The average calculated after the memory test is "statistic" or, more specifically, "descriptive statistic." "Inferential statistic" or "parameter" would be incorrect because the average describes only the data in the sample.
What additional information is obtained from measurements on a ratio scale compared to measurements on an interval scale?
A ratio scale provides information about the ratio of two measurements, which allow comparisons such as "twice as much.
What is the first step in the calculation of (ΣX)^2? a. Square each score. b. Add the scores. c. Subtract 2 points from each score. d. Add the X - 2 values.
b. Add the scores.
A researcher is interested in the Netflix binge-watching habits of American college students. A group of 50 students is interviewed and the researcher finds that these students stream an average of 6.7 hours per week. For this study, the average of 6.7 hours is an example of a(n) . a. parameter b. statistic c. population d. sample
b. statistic
When measuring height to the nearest inch, what are the real limits for a score of 68.0 inches? a. 67 and 69 b. 67.5 and 68.5 c. 67.75 and 68.75 d. 67.75 and 68.25
b. 67.5 and 68.5
1. What value is represented by the lowercase letter n? a. The number of scores in a population b. The number of scores in a sample c. The number of values to be added in a summation problem d. The number of steps in a summation problem
b. The number of scores in a sample
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?
The variable of height is continuous so there are an infinite number of possible values within the real limits of the score. The score of 70 inches, rounded to the nearest whole inch, has the following real limits: 69.5 ≤ X < 70.5
Gentile, Lynch, Linder, and Walsh (2004) surveyed more than 600 8th- and 9th-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(敵対) and had more frequent arguments with teachers. Is this an experimental or a nonexperimental study? Explain your answer
This is not an experiment because no independent variable is manipulated. They are comparing two preexisting groups of individuals based on their level of experiencing video game violence.
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. c. The average number that the researcher calculated is an example of a -----------.
c. The average number that the researcher calculated is an example of a statistics. 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.
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. c. The group that received decaffeinated coffee is a(n)-----------. d. The group that received caffeinated coffee is a(n)-----------.
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.
Deters and Mehl studied the effect of FB status updates on feelings of loneliness. 86 participants were randomly assigned to 2 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. c. Is this an experimental or nonexperimental study? Explain. d. The group that was instructed to post more status updates is a(n) -------------group .
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.
2. What is the value of Σ(X - 2) for the following scores: 6, 2, 4, 2? a. 12 b. 10 c. 8 d. 6
d. 6
The professor in a communications class asks students to identify their favorite reality television show. The different television shows make up a scale of measurement. a. nominal b. ordinal c. interval d. ratio
a. nominal
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. ΣXY b. ΣXΣY c. Σ(Y-X) d. ΣX
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 ---------.
5. a. Statistic (or descriptive statistic) b. Parameter
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.
a. The population consists of all high school students in U.S. b. The sample is the group of 100 students who were measured in the study.
A researcher records the number of bites a goat takes of different plants. The variable, number of bites, is an example of a variable. a. discrete b. continuous c. nominal d. ordinal
a. discrete
A researcher studies the factors that determine the length of time a consumer stays on a website before clicking off. The variable, length of time, is an example of a ---------variable. a. discrete b. continuous c. nominal d. ordinal
b. continuous
What additional information is obtained from measurements on an interval scale compared to measurements on an ordinal scale?
An interval scale provides information about the magnitude of the difference between two measurements.
3. Statistical techniques that use sample data to draw conclusions about the population are . a. population statistics b. sample statistics c. descriptive statistics d. inferential statistics
d. inferential statistics
Define the terms statistic and parameter and explain how these terms are related to the concept of sampling error.
A parameter is a characteristic, usually a numerical value, which describes a population. A statistic is a characteristic, usually numerical, that describes a sample. Although sample statistics are generally good estimates of certain population parameters, they are not perfect. Therefore, there typically is some discrepancy不一致 between the statistics from a sample and the corresponding parameters of the population. This naturally occurring discrepancy is called sampling error.
Ranking jobs, taking into account growth potential, work-life balance, and salary, would be an example of measurement on a(n) ____________ scale. a. nominal b. ordinal c. interval d. ratio
b. ordinal
What additional information is obtained from measurements on an ordinal scale compared to measurements on a nominal scale?
An ordinal scale provides information about the direction of difference (greater or less) between two measurements.
Describe the data for a correlational research study and explain how these data are different from the data obtained in experimental and non-experimental 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.
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?
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.
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.
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. What research design did this study use? a. Correlational b. Experimental c. Non-experimental d. Non-correlational
c. Non-experimental
Which of the following is most likely to be a purely correlational study? a. One variable and one group b. One variable and two groups c. Two variables and one group d. Two variables and two groups
c. Two variables and one group
