Statistics - EDPS Exam 1 Review Homework Questions

When constructing a frequency polygon, the x-axis represents the frequency counts. a) True b) False

b) False

The mean of a z distribution is always: a) 0. b) 1. c) 10. d) 100.

a) 0.

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) The distribution of means is more tightly packed.

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) There is a linear relationship.

A grouped frequency table is recommended when reporting frequencies of a continuous variable. a) True b) False

a) True

A time series plot is a form of a line graph. a) True b) False

a) True

A variable measured on an ordinal scale is never continuous. a) True b) False

a) True

A z statistic is a mean score that has been standardized. a) True b) False

a) True

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) True

In a sample, the sum of the deviations from the mean is always zero. a) True b) False

a) True

It is impossible to have made a Type II error when we have rejected the null hypothesis. a) True b) False

a) True

Random assignment is a critical component of correlational research. a) True b) False

a) True

The mean is the measure of central tendency that is most susceptible to the effects of outliers. a) True b) False

a) True

The variance of a z distribution is always 1. a) True b) False

a) True

We can never prove the null hypothesis. a) True b) False

a) True

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) Type I error.

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) With random assignment, research participants are randomly placed into one of the

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) an outlier.

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) between-groups research design.

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) reject the null hypothesis.

A frequency polygon: a) resembles a city skyline. b) has many crisscrossing lines. c) is a line graph. d) is only useful for discrete data sets.

a) resembles a city skyline. c) is a line graph.

The scores for a very easy exam would probably form a positively skewed distribution. a) True b) False

b) False

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) the midpoint for each interval.

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) the program developed by the sports psychologist

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) the variable of interest; frequencies

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) unimodal

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. the sample size increases.

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) 8

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) Bar graphs typically provide scores for nominal data, whereas histograms typically provide frequencies for scale data.

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) False

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) His exam grades are reliable but lack validity.

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 normal distribution is skewed

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) consuming more fruits and vegetables

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) descriptive

Based on the actual outcome of many, many trials, the liklihood of an event occurring is called: a) personal probability. b) expected relative-frequency probability. c) subjective probability. d) outcome-success-trail probability.

b) expected relative-frequency probability.

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) null hypothesis.

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) random sample.

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) standard error.

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) take the square root of the variance.

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) x axis - independent variable; y axis - dependent variable

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) It is the best way of controlling confounding variables.

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) Probability = successes/trials

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

c) both inferential and descriptive

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) it has an inverted U shape

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) playing ability

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) ratio

Indicate the scale of measurement for temperature. a) nominal b) ordinal c) ratio d) interval

c) ratio d) interval

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) the mode

A normal distribution of standardized scores is called the: a) standard normal distribution. b) null distribution. c) z distribution. d) sample distribution.

c) z distribution.

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) 102, 103, 104, 105, 106, 112

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) All of these are correct.

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.

d) confounded research design.

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) grouped frequency table.

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) mean.

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) number of standard deviations a particular score is from the mean.

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) the central limit theorem

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) the whole population.

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) time series plot.

The average of the squared deviations from the mean is referred to as the: a) standard deviation b) median c) range d) variance

d) variance

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) we almost never have access to the whole population from which to select the sample.