Stats Exam 1 review
The mean is the measure of central tendency that is most susceptible to the effects of outliers. a) True b) False
A
A grouped frequency table is recommended when reporting frequencies of a continuous variable. a) True b) False
A
A sports psychologist developed a program to improve a team's playing ability. The sports psychologist measured each student's playing ability before and after his program to determine whether students would play better. He found that after his program students played significantly better. However, many students later reported that they had also begun consuming more fruits and vegetables within the same time frame to help them play better. In this example, what is the independent variable? a) the program developed by the sports psychologist b) playing ability c) consuming more fruits and vegetables d) the sports psychologist
A
A time series plot is a form of a line graph. a) True b) False
A
A variable measured on an ordinal scale is never continuous. a) True b) False
A
According to Table 2-4 in Question 1, what is the number of volcanoes that corresponds to the highest count of countries? a) 1 b) 2 c) 4 d) 17
A
Consider the following distribution of scores: 2, 2, 8, 10, 10, and 37. Within the context of this distribution, the number 37 would represent: a) an outlier. b) the range. c) the mode. d) the variance.
A
If a researcher has measured their dependent variable on a nominal scale, it is impossible to determine which of two individuals has the higher score. a) True b) False
A
In a histogram, we label our x-axis with ______ and our y-axis with _____. a) the variable of interest; frequencies b) frequencies; the variable of interest c) total cumulative frequency; the variable of interest d) percentiles; frequencies
A
In a sample, the sum of the deviations from the mean is always zero. a) True b) False
A
Jamie is randomly assigned to participate in the experimental condition, and Marie is randomly assigned to participate in the control condition of a research study. The research study must be a: a) between-groups research design. b) within-groups research design. c) correlational research design. d) confounded research design.
A
Professor Green is interested in determining the average SAT score for the entire population of individuals who took the SAT. She wants to know how her class compares to the population of students who took the SAT. She finds that the average SAT score for the population is 1000. Is this score an example of a descriptive or an inferential statistic? a) inferential b) descriptive c) both inferential and descriptive d) none of the above
A
Professor Wiggums completes a research study that shows that students who spend more time studying for an exam tend to get a higher score on the exam. Based on this conclusion, what can be said of the variables of "study-time" and "exam-score"? a) There is a linear relationship. b) There is a nonlinear relationship. c) There is no relationship. d) There is a curvilinear relationship.
A
Random assignment is a critical component of correlational research. a) True b) False
A
When constructing a histogram for data in a grouped frequency table, we have to calculate: a) the midpoint for each interval. b) the range of scores. c) the cumulative frequency for each interval. d) the total of all the frequencies.
A
Which of the following terms best describes the following distribution of scores: 2, 3, 7, 7, 7, 7, 8, 10, 10, and 15? a) unimodal b) bimodal c) multimodal d) all of these
A
What is the confounding variable in the previous example? a) the sports psychologist b) consuming more fruits and vegetables c) playing ability d) program developed by the sports psychologist
B
A normal distribution is a specific frequency distribution that has all of the following characteristics EXCEPT: a) a normal distribution is bell-shaped. b) a normal distribution is skewed. c) a normal distribution has symmetry. d) a normal distribution is a unimodal curve.
B
A statistics instructor is interested in determining the average SAT score of students in her class. The instructor finds that, on average, students in her statistics class scored an 1140 on their SATs. Is this score an example of a descriptive or an inferential statistic? a) inferential b) descriptive c) both inferential and descriptive d) none of these
B
Dr. Marbles decides to adopt an unconventional (and rather inappropriate) way of assigning grades to students in his Introductory Psychology class. Three times throughout the semester, he has his students line up from tallest to shortest. He then assigns A's to the fifth of the class that is shortest, B's to the next fifth of shortest students, and so on (so that the fifth of the class that is tallest receives F's). At the end of the semester, Dr. Marbles averages across these grades to determine a final grade. While Dr. Marbles's grading methods may seem problematic, which of these statements is true about the students' exam grades? a) His exam grades are valid but lack reliability. b) His exam grades are reliable but lack validity. c) His exam grades are neither reliable nor valid. d) His exam grades are both reliable and valid.
B
Frequency table 2-4 shows the counts for countries according to how many volcanoes there are in each country. How many countries have 5 volcanoes? a) 17 b) 4 c) 3 d) 5 (see picture problem 1 chapter 2)
B
In a scatterplot, on what axes do we put our independent and dependent variables? a) x axis - dependent variable; y axis - independent variable b) x axis - independent variable; y axis - dependent variable c) the independent and dependent variables can be put on either axis d) vertical axis - independent variable; horizontal axis - dependent variable
B
The figures below provide examples of skewness. Which diagram may likely be associated with a ceiling effect? a) figure a b) figure b c) both figures d) neither figure (see figure number 10 chapter 2)
B
The scores for a very easy exam would probably form a positively skewed distribution. a) True b) False
B
To calculate the standard deviation you can: a) square the variance. b) take the square root of the variance. c) square the mean. d) average the scores' deviation from the mean.
B
What is the difference between histograms and bar graphs? a) Bar graphs typically provide scores for ordinal data, whereas histograms typically provide scores for scale data. b) Bar graphs typically provide scores for nominal data, whereas histograms typically provide frequencies for scale data. c) Histograms typically provide scores for nominal data, whereas bar graphs typically provide scores for scale data. d) Bar graphs and histograms are completely identical.
B
What is the median for the following distribution of scores: 2, 2, 8, 10, and 27? a) 2 b) 8 c) 27 d) 9.8
B
When constructing a frequency polygon, the x-axis represents the frequency counts. a) True b) False
B
3. You are scheduled to visit your physician for a checkup. Your doctor performs a routine medical exam, which includes measuring your height and weight in addition to your blood pressure and temperature. Indicate the scale of measurement for height. a) nominal b) ordinal c) ratio d) interval
C
A frequency polygon: a) resembles a city skyline. b) has many criss-crossing lines. c) is a line graph. d) is only useful for discrete data sets.
C
What is the dependent variable in the previous example? a) the sports psychologist b) consuming more fruits and vegetables c) playing ability d) program developed by the sports psychologist
C
What, if anything, is wrong with the graph below? a) The graph does not identify the independent and dependent b) The graph contains excessive "chartjunk," such as moiré vibrations, and is difficult to interpret as a result. c) The axis does not begin with 0 and, as a result, the differences between means are exaggerated. d) There is nothing wrong with the graph. (see picture chapter 3 #6)
C
Which statement addresses why random assignment of participants to conditions is necessary for an experiment? a) It puts all of the confounding variables in one group. b) It makes the independent variable equal to the dependent variable. c) It is the best way of controlling confounding variables. d) It allows the participants to choose which experimental condition of the study to partake in.
C
Which type of measure of central tendency is most appropriate to use when one particular score dominates a distribution and/or the data are at the nominal level? a) the mean b) the median c) the mode d) none of these
C
A parameter is a number based on: a) the most frequently occurring score in a distribution of scores. b) the variance of scores. c) a sample taken from a population. d) the whole population.
D
A type of graph that plots a scale variable (on the y-axis) as it changes over an increment of time (plotted on the x-axis) is called a: a) histogram. b) scatterplot. c) pie chart. d) time series plot.
D
Indicate the scale of measurement for temperature. a) nominal b) ordinal c) ratio d) interval
D
Maria wants to calculate her current grade for her statistics class. She adds together her scores for Exam 1, Exam 2, and Exam 3. She then divides this total by 3, the number of exams. Maria has just calculated her: a) variance. b) mode. c) median. d) mean.
D
The average of the squared deviations from the mean is referred to as the: a) standard deviation b) median c) range d) variance
D
When data cover a huge range (such as populations of countries), it makes sense to construct a: a) frequency table. b) histogram. c) bar graph. d) grouped frequency table.
D
Which of the following distribution of scores has a range of 10? a) 2, 6, 7, 9 10 b) 9, 9, 10, 11, 11 c) 3, 10, 10, 10, 10, 14 d) 102, 103, 104, 105, 106, 112
D
Which of the following is an example of a measure of central tendency? a) the mean b) the median c) the mode d) All of these are correct.
D
Experiment: student in a room with white walls, one table and a chair in the center of the room they had to read a story. After they read the story they were asked to drink orange drink which had either high levels of caffeine or no levels of caffeine. Then, they had to sit and wait 30 min to an hour. Then they had to write down everything they remembered from the story. What was the independent variable in the study and what were the levels?
High caffeine drink, no caffeine
A distribution of scores, drawn from a normal population, will more closely resemble a normal curve as: a) the sample size increases b) the sample size decreases c) more outliers are added to the sample d) scores are converted to z scores
a
A z statistic is a mean score that has been standardized. a) True b) False
a
Dr. Gullums completes an experiment where the mean of the experimental group is significantly higher than the mean of the control group (as she had hypothesized). This will lead Dr. Gullums to: a) reject the null hypothesis. b) fail to reject the null hypothesis. c) reject the research hypothesis. d) all of these are true
a
How is a distribution of sample means different from a distribution of raw scores? a) The distribution of means is more tightly packed. b) The distribution of means has a greater standard deviation. c) The distribution of means cannot be plotted on a graph. d) All of these are true.
a
If we reject the null hypothesis, but it was a mistake to do so, this action is called a: a) Type I error. b) Type II error. c) Type III error. d) All of these are correct.
a
It is impossible to have made a Type II error when we have rejected the null hypothesis. a) True b) False
a
The mean of a z distribution is always: a) 0. b) 1. c) 10. d) 100.
a
The variance of a z distribution is always 1. a) True b) False
a
We can never prove the null hypothesis. a) True b) False
a
Which of the following statements is TRUE about random assignment? a) With random assignment, research participants are randomly placed into one of the conditions of the experiment. b) With random assignment, research participants are randomly selected into a study from a population. c) Random assignment is necessary when designing a correlational research study. d) Random assignment will result in a flawed research design.
a
A distribution of sample means will always be more variable than the population of scores from which those samples were drawn. a) True b) False
b
A sample in which every member of the population has an equal chance of being selected into the study is called a: a) convenience sample. b) random sample. c) general sample. d) volunteer sample.
b
Based a) personal probability. on the actual outcome of many, many trials, the likelihood of an event occurring is called: b) expected relative-frequency probability. c) subjective probability. d) outcome-success-trail probability.
b
The standard deviation of a distribution of means is called the: a) standard score. b) standard error. c) central limit theorem. d) normal curve.
b
The statement that postulates that there is no difference between populations (or that the difference is in a direction opposite from that anticipated by the researcher) is called the: a) experimental hypothesis. b) null hypothesis. c) research hypothesis. d) rejected hypothesis.
b
A normal distribution of standardized scores is called the: a) standard normal distribution. b) null distribution. c) z distribution. d) sample distribution.
c
All of the following are true of the normal curve EXCEPT: a) it is bell shaped. b) it is unimodal. c) it has an inverted U shape. d) it is symmetric.
c
The research study conducted by the sports psychologist in the previous example is a: a) between-groups research design. b) within-groups research design. c) correlational research design. d) confounded research design.
c
Which formula should you use to calculate probability? a) Probability = failures/trials b) Probability = outcomes/trials c) Probability = successes/trials d) Probability = trials/successes
c
The assertion that a distribution of sample means approaches a normal curve as sample size increases is called: a) Bayes' theorem. b) the normal theorem. c) De Moivre's theorem. d) the central limit theorem.
d
Label the following variables as discrete or continuous and nominal, ordinal, interval, or ratio. net worth
continuous, interval
Label the following variables as discrete or continuous and nominal, ordinal, interval, or ratio. Number of books owned
continuous, ratio
Truly random samples are rarely used in research in the social sciences because: a) there is no way to know if a sample is random. b) people vary too much, from person to person, in order for them to be randomly selected. c) science has not yet developed the methods and procedures to allow for us to randomly select from a population. d) we almost never have access to the whole population from which to select the sample.
d
a z score is defined as the: a) mean score b) square of the mean score c) square of the difference or deviation a score is from the mean d) number of standard deviations a particular score is from the mean
d
Label the following variables as discrete or continuous and nominal, ordinal, interval, or ratio. colors
discrete, nominal
Label the following variables as discrete or continuous and nominal, ordinal, interval, or ratio. Billboard Top 10 rankings
discrete, ordinal
Label the following variables as discrete or continuous and nominal, ordinal, interval, or ratio. house numbers
discrete, ordinal
Experiment: student in a room with white walls, one table and a chair in the center of the room they had to read a story. After they read the story they were asked to drink orange drink which had either high levels of caffeine or no levels of caffeine. Then, they had to sit and wait 30 min to an hour. Then they had to write down everything they remembered from the story. what are some confounding variables in this experiment?
eat before, memory in general, tolerance to caffeine
What temperature is it outside today? nominal, ordinal, interval, or ratio?
interval
Experiment: student in a room with white walls, one table and a chair in the center of the room they had to read a story. After they read the story they were asked to drink orange drink which had either high levels of caffeine or no levels of caffeine. Then, they had to sit and wait 30 min to an hour. Then they had to write down everything they remembered from the story. What was the dependent variable in this study and how might it have been measured?
memory of the story how many things remembered
What year are you in school? nominal, ordinal, interval, or ratio?
nominal
On a scale of 1 to 10, how comfortable do you feel about doing math? nominal, ordinal, interval, or ratio?
ordinal
random selection or random assignment? in a study of phobias, 30 rhesus monkeys were either exposed to fearful stimuli or not exposed to fearful stimuli. Every monkey had an equal chance of being placed in either of the exposure conditions
random assignment
random selection or random assignment? In a study of visual perception, 120 introduction to psychology students were recruited to participate
random selection
random selection or random assignment? a study of services offered by counseling centers at Canadian universities studied 20 universities; every Canadian university had an equal chance of being in the study
random selection
random selection or random assignment? in a study of cell phone usage, participants were recruited by including along with their cell phone bill an invitation to participate in the study
random selection
How many cups of coffee do you have in a day? nominal, ordinal, interval, or ratio?
ratio
What is your height in inches? nominal, ordinal, interval, or ratio?
ratio
