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)