UNC PSYC 210 Midterm Quiz Questions

What is the primary purpose of learning about statistics?

a. to discuss what kind of distribution you have

b. so you can overwhelm your opponents with numbers

c. to learn the purpose of the standard normal distribution

d. so you can make a claim and support it with evidence

D. so you can make a claim and support it with evidence

what do we mean when we use the term "variable" in statistics?

a. an orderly way to assign numbers to observations

b. label that refers to some abstract concept that might differ between people

c. coding characteristics of human behavior into discrete categories

d. the way we measure an abstract construct

b. label that refers to some abstract concept that might differ between people

assessing how happy UNC students are on a 7 point scale (1 not very happy to 7 extremely happy) would be best achieved using what type of scale?

a. nominal

b. ordinal

c. interval

d. ration

c. interval

in a frequency distribution graph, frequencies are presented on the ______ and the scores (categories) are listed on the _______.

a. x axis; y axis

b. class interval; horizontal line

c. horizontal line; vertical line

d. y axis; x axis

d. y axis; x axis

the preferred graph to display the frequency of variables measured on a nominal scale is a:

a. relative frequency polygon

b. histogram

c. cumulative frequency polygon

d. pie chart

d. pie chart

using letter grades (A, B, C, D, and F) to classify student performance is an example of measurement on a(n) _________ scale of measurement.

a. ordinal

b. ratio

c. interval

d. nominal

a. ordinal

for a relative frequency histogram, each point on the graph represents

a. the percent of scores at a particular point or interval

b. the percent of scores above a particular point or interval

c. the percent of scores at or below a particular point or interval divided by the total number of scores

d. the percent of scores above a particular point or interval divided by the total number of scores

a. the percent of scores at a particular point or interval

the heights of columns on a histogram indicate the:

a. average scores

b. value of the score being graphed

c. number of scores in a particular interval

d. the midpoints of the various intervals

c. number of scores in a particular interval

what is one way to simplify variables with many, many levels (or decimal places) when creating a frequency distribution?

a. graph each level of the variable individually

b. organize data into class intervals

c. ignore outliers

d. compute a mean, median, and mode

b. organize data into class intervals

what is the purpose of a pie chart, histogram, or polygon?

a. to see what your distribution looks like before performing any statistical tests

b. to visually display otherwise confusing numbers

c. to utilize current technology to present relevant statistics

d. both a and b

d. both a and b

when would the mode be the most effective way to describe a distribution?

a. when the mean, median, and mode are the same and you have a continuous variable

b. when the mean, median, and mode are the same and you have a categorical variable

c. when data are categorical with few categories

d. the mode is never appropriate

c. when data are categorical with few categories

kurtosis refers to:

a. whether more extreme scores are in one tail of the distribution as opposed to other

b. the average distance of scores from a measure of central tendency

c. the peakedness or flatness of a distribution

d. whether the distribution is continuous or discrete

c. the peakedness or flatness of a distribution

why is the mean the most commonly used measure of central tendency?

a. it isn't the most commonly used

b. the median and mode don't tell us much when variables are discrete

c. it gives us one, simple number that minimizes deviations overall

d. the mean is more appropriately used to describe variability

c. it gives us one, simple number that minimizes deviations overall

which of the following values of a distribution's variance is impossible?

a. 1025

b. -.449

c. 2.45

d. .965

b. -.449

why are measures of variability so important?

a. because measures of central tendency are so flawed

b. because standard deviations and range are good measures representing a distribution

c. because it tells us how good our measures of central tendency are

d. because statistics are used only to report variance

c. because it tells us how good our measures of central tendency are

why do we transform scores?

a. to get a mean and standard deviation

b. to make different distributions comparable

c. to make life more complicated

d. to change scores to raw units

b. to make different distributions comparable

the central limit theorem tells us that the shape of a sampling distribution of means approaches a normal distribution as:

a. the population distribution approaches a normal distribution

b. the standard deviation of the population approaches the standard error of the mean

c. the mean of the population distribution gets larger

d. the size of the samples gets larger

d. the size of the samples gets larger

the process of selecting a subset of people from a population such that every person in the population has an equal chance of being chosen for the subset is called:

a. standardizing the population

b. stimulus sampling

c. random sampling

d. population sampling

c. random sampling

a researcher is curious about the average IQ of all currently registered voters in the state of Iowa. If this average could be obtained, it would be an example of a __________.

a. parameter

b. statistic

c. sample

d. population

d. population

if we say something is "statistically significant", what do we mean?

a. our results are likely just due to chance

b. our results are unlikely to be found by chance

c. we have proven that our data is different from a population

d. we have disproved that our data is different from a population

b. our results are unlikely to be found by chance

a researcher says that her analysis shows that the effect of the independent variable on the dependent variable is statistically significant. This means that the effect is:

a. very unlikely to occur by chance

b. very unlikely to be large

c. very likely to be predictable

d. very likely to be found again upon replication

a. very unlikely to occur by chance

in hypothesis testing, a type I error is:

a. rejecting the null hypothesis when the null hypothesis is false

b. rejecting the null hypothesis when the null hypothesis is true

c. failing to reject the null hypothesis when the null hypothesis is false

d. failing to reject the null hypothesis when the null hypothesis is true

b. rejecting the null hypothesis when the null hypothesis is true

in hypothesis testing, a type II error is:

a. rejecting the null hypothesis when the null hypothesis is false

b. rejecting the null hypothesis when the null hypothesis is true

c. failing to reject the null hypothesis when the null hypothesis is false

d. failing to reject the null hypothesis when the null hypothesis is true

c. failing to reject the null hypothesis when the null hypothesis is false

in hypothesis testing, power is defined as the probability of:

a. rejecting the null hypothesis when the null hypothesis is false

b. rejecting the null hypothesis when the null hypothesis is true

c. failing to reject the null hypothesis when the null hypothesis is false

d. failing to reject the null hypothesis when the null hypothesis is true

a. rejecting the null hypothesis when the null hypothesis is false

if one were testing whether a particular sample was drawn from a population with a particular mean and the standard deviation of the entire population was known, one would use the ________ test to statistically answer the question.

a. Z

b. T

c. R

d. F

a. Z

the alternative hypothesis for an independent-measures t test states ______________.

a. u1 + u2 = 0

b. M1 - M2 not equal to 0

c. u1 - u2 not equal to 0

d. M1 - M2 = 0

c. u1 - u2 not equal to 0

an assumption of the independent samples t-test is that the populations from which the samples were drawn have equal variability. This assumption is known as:

a. independence

b. outcomes are normally distributed

c. homogeneity of variance

d. heterogeneity of variance

c. homogeneity of variance

what type of test is most appropriate when you want to compare an outcome between the same people at two different time points?

a. regression and correlation analysis

b. correlated samples t-test

c. independent samples t-test

d. t-test for correlations

b. correlated samples t-test

what type of test is most appropriate when you want to compare an outcome between two groups with different people in each group?

a. regression and correlation analysis

b. correlated samples t-test

c. independent samples t-test

d. t-test for correlations

c. independent samples t-test

why is regression analysis so important in the social sciences?

a. because it gives us an exact outcome for a given predictor

b. because it allows us to predict important outcomes

c. because it has no variance

d. because it used both means and standard deviations

b. because it allows us to predict important outcomes