Lectures 1-4

pie chart

In a _____, pieces represent percentages of the whole pie, and the percentages add up to 100.

qualitative

A _____ (categorical) variable classifies an individual based on some characteristic; examples include race, major, personality type, and type of exercise.

quantitative

A _____ (measurement) variable indicates the amount of a variable that is present; examples include age, intelligence, number of symptoms, and number of correct answers.

bar graph; histogram

A _____ illustrates frequencies per level/category of qualitative (categorical) data. Notably, in contrast to a _____, the bars do not touch; this illustrates the discontinuity between categories.

histogram; bar graph

A _____ illustrates frequencies per level/category of quantitative (measurement) data. Notably, in contrast to a _____, categories are arranged in numerical order, and the bars touch to show continuity between adjacent categories.

line graph

A _____ is used when graphing experimental results, often with two or three variables.

discrete

A _____ variable takes on a small set of possible values; in most cases, no values are possible between adjacent units on the scale.

continuous

A _____ variable takes on any value; in most cases, values are theoretically possible at all points on the scale (i.e., there are an infinite number of points).

ratio

A(n) _____ scale (the highest level of measurement) has all of the properties of an interval scale as well as an absolute zero point; examples include temperature (Kelvin), reaction time, weight, and height.

1

An r^2 value of 0.01 indicates that _____% of the variability in y is accounted for by the variability in x.

0.64

An r^2 value of _____ indicates that 64% of the variability in y is accounted for by the variability in x.

covariance

Correlation is equal to the _____ standardized/transformed to fit a scale ranging from -1.0 to +1.0.

direction; strength

Correlation is measured with a correlation coefficient (r), the possible values of which range from -1.0 to 1.0. For r, the sign indicates _____, and the numerical part indicates _____.

histogram

Design guidelines for a _____ include: (1) two few/too many categories can distort the shape of the distribution; (2) intervals are mutually exclusive (a data point can fall into only one category/interval); (3) the distribution should contain 6-12 intervals.

correlation; regression

In _____, we establish whether or not a relationship exists; _____ takes this a step further by using the value of one variable to predict the value of another variable.

2

For this class, the final answer should have at least _____ decimal places.

continuous

Histograms, line graphs, and scatterplots are used to present _____ variables.

breaks

If the axes of a graph do not intersect at 0, _____ should be used.

interval

In a(n) _____ scale (the second-highest level of measurement), numbers represent magnitude, and there are equal intervals between adjacent units; examples include temperature (Celsius and Fahrenheit) and standardized test scores.

ordinal

In a(n) _____ scale (the second-lowest level of measurement), numbers have some meaning, but the magnitude between adjacent ranks may not be equal.

interval

In a(n) _____ scale, there is no absolute zero point; this means that while negative numbers are possible, a value of zero (0) does not indicate the absence of something.

statistical analyses

Knowing the level/scale of measurement is important because it dictates the allowable _____.

continuous

Less common data presentation types for _____ variables include stem and leaf plots, box plots, and frequency distributions.

inference; representative

Making a(n) _____ involves generalizing from a sample to the broader population, which requires _____ samples.

ordinal; interval

Most psychological measurements are truly _____ but are treated as _____ measures to streamline statistical analysis.

linear

Pearson's correlation coefficient (r) as well as the least-squares regression line assume that data have a _____ association.

categorical

Pie charts and bar graphs are used to present _____ data.

lower

Range restriction usually results in a _____ correlation, thereby giving us a less accurate picture of the actual relationship.

sample; population

Statistic is to _____ as parameter is to _____.

cumulative frequency

Symbolized by cf, _____ is the number of scores that fall at or below a particular score; to compute, add simple frequencies for all scores below the score with the frequency for the score.

frequency

Symbolized by f, _____ is the number of times a given score occurs.

false

T/F: Correlation implies causation.

false

T/F: Random sampling guarantees representativeness.

false

T/F: Regression of y on x is the same as regression of x on y.

true

T/F: The least-squares regression line always includes the means (x bar, y bar) as a point.

false

T/F: The least-squares regression line can be used on ranges outside of the variables on which it was developed.

true

T/F: The y-axis should be about 2/3 to 3/4 of the length of the x-axis to avoid distortion.

true

T/F: There is only one "best fit line" for each set of data.

coefficient of determination

The _____ (r^2, also referred to as the effect size measure) is a measure of predictive power that represents the usefulness/meaningfulness of a correlation.

least-squares

The _____ regression line gives the best estimate of y (DV) given a corresponding x (IV); this means that this line gives the greatest overall accuracy in prediction compared to any other line of fit.

least-squares

The best regression line is the one that produces the smallest squared errors of prediction; this is referred to as the _____ regression line.

variables

The categories of _____ include (1) independent vs. dependent; (2) quantitative vs. qualitative; and (3) discrete vs. continuous.

graphs; tables

The two main categories of data presentation include (abc) _____ and _____; this class focuses on the former.

relationships

There are three main ways to categorize _____ in statistics: (1) linear vs. curvilinear; (2) positive vs. negative; and (3) perfect vs. imperfect.

descriptive; inferential

There are two main branches of statistics (abc): _____ and _____.

statistics; parameters

_____ are used as estimates of _____.

scales of measurement

_____ are used to characterize rules for assigning numbers to objects; they include (1) nominal; (2) ordinal; (3) interval; and (4) ratio.

parameters

_____ are usually denoted by Greek letters.

extreme scores

_____ can dramatically change the value of r and, by extension, change the interpretation of the relationship; this effect can be rectified by graphing data.

covariance; correlation

_____ indicates how variables vary together. However, this is not used because it is difficult to interpret and does not account for the standard deviation of each variable; thus, _____ is used instead.

nominal

_____ is the lowest level of measurement and is used with qualitative variables; examples include football numbers, names, colors, and disorders.

correlation; regression

_____ is used to assess a relationship, whereas _____ is used for prediction.

N; n

_____ represents the overall total number of participants or scores, and _____ represents the total number of participants or scores in a group or condition.

inferential

_____ statistics are used to make decisions and include such analyses and tests as z-tests, t-tests, and ANOVA.

descriptive

_____ statistics summarize data; examples include central tendency measures (mean, median, mode), variability (standard deviation, variance, range), and shape (symmetry, skew).

population

a complete set of whatever we are studying

proportion

a fraction of the total, which is represented as a decimal number between 0 and 1

scatterplot

a graphed cluster of dots, each of which represents the values of two variables

random sampling

a strategy of selecting study participants that intends to improve the representativeness of a sample

sample

a subset of a population, which consists of participants

percent

a transformation of proportion (i.e., proportion times 100), which ranges from 0 to 100 and is denoted by %

independent variable

a variable that is changed or manipulated

dependent variable

a variable that is measured under each condition of the independent variable

parameter

any measurement on a population; a number calculated on a population that quantifies a characteristic of a population

statistic

any measurement on a sample; a number calculated on a sample that quantifies a characteristic of a sample

variable

anything that -- when measured -- can produce two or more different values

measurement

rules for assigning numbers to objects to represent quantities of attributes

r^2

the coefficient of determination; indicates the proportion of the total variability in y that is accounted for by the variability in x

1 - r^2

the coefficient of non-determination; indicates the proportion of the total variability in y that is NOT accounted for by the variability in x

cumulative percentage

the percentage of scores that fall at or below a particular score; compute by dividing the cumulative frequency by the total number of scores and multiplying by 100

relative frequency

the proportion of the total number of scores that occur in a given interval; equal to the frequency divided by the total number of scores (f/N)