Study your flashcards anywhere!
Download the official Cram app for free >
 Shuffle
Toggle OnToggle Off
 Alphabetize
Toggle OnToggle Off
 Front First
Toggle OnToggle Off
 Both Sides
Toggle OnToggle Off
 Read
Toggle OnToggle Off
How to study your flashcards.
Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key
Up/Down arrow keys: Flip the card between the front and back.down keyup key
H key: Show hint (3rd side).h key
A key: Read text to speech.a key
136 Cards in this Set
 Front
 Back
Alternative hypothesis

a research hypothesis


Bar chart

a graphic that displays how data fall into different categories or groups


Bellshaped curve

symmetrical, singlepeaked frequency distribution


Bias

the consistent underestimation or overestimation of a true value


Bimodal

curve with two equal scores of highest frequency


Binomial

even with only two possible outcomes


Bivariate

involving two variables


Box Plot

(box and whiskers) a graphic display of data indicating symmetry and central tendency


Central Limit Theorem

a rule that states that the smapling distribution of means from any population will be normal for a large sample n.


Central tendency

a statistical measure to determine a single score that defines the center of a distribution. The goal is to find the single score that is most typical or most representative of the entire group.


Chisquare

a probability distribution used to test the independence of two nominal variables


Class frequency

the number of observations that fall into each class interval


Class intervals

categories or groups contained in frequency graphics


Coefficient of determination

a measure of the proportion of wach other’s variability that two variables share


Confidence interval

the range of values that a population parameter could take at a given level of significance


Constant

characteristic or condition that does not vary but is the same for every individual


Constructs

internal attributes or characteristics that cannot be directly observed bt are useful for describing and explaining behavior


Continuous level

the probability of obtaining a given result by chance


Continuous variable

a variable that can be measured with whole numbers and fractional (or decimal) parts thereof


Control condition

do not receive experimental treatment. Instead, they receive no treatment or they receive a neutral, placebo treatment. Purpose of control condition is to probide baseline for comparison with the experimental condition.


Correlation coefficient

a measure of the degree to which two variables are linearly related


Correlational method

two variables are observed to determine whether there is a relationship between them


Critical value

the value of a computed statistic used as a threshold to decide whether the null hypothesis will be rejected


Data

Plural, measurements or observations; numerical information about variables


Datum

singular; single measurement or observation; commonly called score or raw score


Degrees of freedom

a parameter used to help select the critical value in som probability distributions


Dependent events

events such that the outcome of one has an effect on the probability of the outcome of the other


Dependent variable

a variable that is caused or influenced by another


Descriptive statistics

numerical data that describe phenomena


Directional test

a test of the prediction that one value is higher than another


Discrete variable

a variable that can be measured only by means of whole umbers


Disjoint occurrence

both outcomes unable to happen at the same time


Distribution

a collection of measurements; how scores tend to be dispersed about a measurement scale


Dot plot

a graphic that displays the variability in a small set of measures


Experimental method/condition

one variable is manipulated while another variable is observed and measured. To establish a causeandeffect relationship between the two variables, an experiment attempts to control all other variables to prevent them from influencing the results


Frequency distribution

an organized tabulation of the number of individuals located in each category on the scale of measurement


Frequency histogram

a graphic that displays how many measures fall into different classes


Frequency polygon

a graphic presentation of frequency of a phenomenon that typically uses straight lines and points.


Grouped data

represented in a frequency table, formula for sample mean for grouped data xbar = Σfx n where f is frequency and x is midpoint





Grouped measures

a set of values that belong to the same class


Histogram

a graphic presentation of frequency of a phenomenon


Independent events

events such that the outcome of one has no effect on the probability of the outcome of the other


Independent variable

variable that is manipulated by the researcher. Usually consists of the two (or more) treatment conditions to which subjects are exposed; consists of the anteceent conditions that were manipulated prior to observing the dependent variable.


Inference

conclusion about the population parameter based upon analysis of a sample statistic


Inferential statistics

consists of techniques that allow us to study samples and then make generalizations about the populations from which they were selected


Intercept

the value of y at which a line crosses the vertical axis


Interquartile range

set of measures lying between the lower quartile (25th percentile) and the upper quartile (75th percentile), inclusive


Interval

a scale using numbers to rank order; its intervals are equal but with with an arbitrary 0 point


Interval scale

consists of ordered categories that are all intervals of exactly the same size. Equal differences between numbers on the scale reflect equal differences in magnitude. Ratios of magnitudes are not meaningful.


Joint occurrence

both outcomes happening simultaneously; P(AB)


Least squares

any lineor curvefitting model that minimizes the squared distance of data points to the line


Lower quartile

(Q1), the 25th percentile of a set of measures


Mean

the sum of the measures in a distribution divided by the number of measures, x(bar)= mean of sample, μ = mean of population, M= sample mean


Measures of central tendency

descriptive measures that indicate the center of a set of values


Median

the middle measure in an ordered distribution, for grouped data= median=L = w (.5n  Σfb)



w = interval width








n =

total number of measurements


w =

interval width


fmed =

frequency of the class containing the median


Σfb =

sum of the frequencies for all classes before the median class


Middle quartile

(Q2), the 50th percentile of a set of measures; the median


Mode

most frequent measure in a distribution


Moundshaped curve

see bellshaped curve


Mutually exclusive

evens such that the occurrence of one precludes the occurrence of the other


Negative relationship

a relationship between two variables such that when one increases, the other decreases


Nominal

a scale using numbers, symbols, or names to designate different subclasses


Nondirectional test

a test of the prediction that two values are equal or a test that they are not equal


Nonparametric test

statistical test used when assumptions about normal distributions in the population cannot be met, or when the level of measurement is ordinal or less


Normal distribution

smooth bellshaped curve symmetrical about the mean such that its shape and area obey the Empircal Rule


Null hypothesis

the reverse of the research hypothesis


Ogive

a graphic that displays a running total


Operational definition

identifies a measurement procedure(a set of operations), for measuring an external behavior and uses the resulting measurements as a definition and measurement of hypothical construct. Has two components= 1)describes a set of operations for measuring a construct; 2) defines the constructin terms of resulting measurements


Onetailed test

a test of the prediction that one value is higher than another


Order of Mathematical Operations

1) any calculation within parenthesis; 2) squaring (or raising to other exponents); 3) multiplying &/or dividing (L→R); 4) summation using the Σ notation; 5) any other addition or subtraction


Ordinal

A scale using numbers or symbols to rank order; its intervals are unspecified


Outlier

a data point that falls far from most other points; a score extremely divergent from the other measures of a set


Parameter

a characteristic of a population


Percentile

the value in an ordered set of measurements such that P% of the measures lie below that value


Percentile rank

the percentage of individuals in the distribution with scores at or below the particular value


Pie chart

a graphic that displays parts of the whole


Point estimate

a number computed from a sample to represent a population parameter


Population

a group of phenomena that have something in common


Positive relationship

a relationship between two variables such that when one increases, the other increases, or when one decreases, the other decreases


Power

the probability that a test will reject the null hypothesis when it is, in fact, false


Probability

a quantitative measure of the chances for a particular outcome or outcomes


Probability distribution

a smooth curve indicating the frequency distribution for a continuous random variable


Qualitative variable

phenomenon measured in kind, that is, non numerical units


Quasiindependent variable

research studies that involve comparing groups that are not created by manipulating an independent variable. Instead, the groups are usually determined by a participant variable, or a time variable (pre,post).


Random error

error that occurs as a result of sampling variability


Rank

the percentage of individuals in the distribution with scores at or below the particular value


Range

difference between the largest and smallest measures of a set


Ratio

a scale using numbers to rank order; its intervals are equal, and the scale has an absolute 0 point


Ratio scale

interval scale with the additional feature of an absolute zero point. Ratios of numbers DO reflect ratios of magnitude


Region of acceptance

the area of a probability curve in which a computed test statistic will lead to acceptance of the null hypothesis


Region of rejection

the area of a probability curve in which a computed test statistic will lead to rejection of the null hypothesis


Regression

a statistical procedure used to estimate the linear dependence of one or more independent variables on a dependent variable


Relative frequency

the ratio of class frequency to total number of measures


Research hypothesis

a prediction or expectation to be tested


Residual

the vertical distance between a predicted value y and its actual value


Sample

a group of members of a population selected to represent the population


Sampling distribution

the distribution obtained by computing a statistic for a large number of samples drawn from the same population


Sampling error

the discrepancy, or amount of error, that exists between a sample statistic and the corresponding population parameter


Sampling variability

the tendency of the same statistic computed from a number of random samples drawn from the same population to differ


Scatterplot

a graphic display used to illustrate degree of correlation between two variables


Skewed

a distribution displaced at one end of the scale and a tail strung out at the other end


Slope

a measure of a line’s slant


Standard deviation

a measure of data variation; the square root of the variance


Standard deviation of a sample

s


Standard deviation of a population

σ


Standard error

a measure of the random variability of a statistic


Standardize

to convert to a zscore


Statistic

a characteristic of a sample


Statistical significance

the probability of obtaining a given result by chance


Statistics

a branch of mathematics that describes and reasons from numerical observations; or descriptive measures of a sample


Stemandleaf

graphic display that shows actual scores as well as distribution of classes


Symmetry

a shape such that one side is the exact mirror image of the other


Systematic error

the consistent underestimation or overestimation of a true value


tdistribution

a probability distribution often used when the population standard deviation is not known or when the sample size is small


tabled value

the value of a computed statistic used as a threshold to decide whether the null hypothesis will be rejected


test statistic

a computed quantity used to decide hypothesis tests


twotailed test

a test of the prediction that two values are equal, or a test that they are not equal


type I error

rejecting the bull hypothesis that is, in fact, true


type II error

failing to reject a null hypothesis that is, in fact, false


upper quartile

(Q3), the 75th percentile of a set of measures


value

a measurement or classification of a variable


variable

an observable characteristic of a phenomenon that can be measured or classified


variance

a measure of data variation; the mean of the squared deviation scores about the means of a distribution


variance of a sample

s2


within treatment variability

scores differing from one another even within a single treatment group; researcher has to consider how to describe and characterize sets of scores before they can be compared


σ2

variance of the population


zscore

a unit of measurement obtained by subtracting the mean and dividing by the standard deviation


Σx

sum of measures


Σx2

sum of the squares of the measures
