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AP Statistics Flashcards

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96553336975 number summaryThe minumum value, lower quartile, median, upper quartile, and maximum value for a data set. These five values give a summary of the shape of the distribution and are used to make box plots. The five numbers that help describe the center, spread and shape of data0
9655333698z scorea measure of how many standard deviations you are away from the norm (average or mean) -Number of standard deviations a score is above or below the mean (positive above, negative below1
9655333699standard deviationA statistical measure of how far away each value is, on average, from the mean. A measure of spread. Specifically, the typical distance the data points are from the mean.2
9655333700population(statistics) the entire aggregation of items from which samples can be drawn What the sample in an experiment or study usually reperesents3
9655333701categorical dataData that can be placed into categories . For example "gender" is a categorical data and the categories are "male" and "female". Labels or names used to identify categories of like items If you asked people in which month they were born or what their favorite class is, they would answer with names, which would be categorical data. However, if you asked them how many siblings they have, they would answer with numbers, not categories Labels or names used to identify categories of like items4
9655333702quantitative dataData associated with mathematical models and statistical techniques used to analyze spatial location and association. numerical information describing how much, how little, how big, how tall, how fast, etc. age is quantitative5
9655333703bar grapha type of graph in which the lengths of bars are used to represent and compare data in categories A graph that uses horizontal or vertical bars to represent data.6
9655333704parameter(n) a determining or characteristic element; a factor that shapes the total outcome; a limit, boundary a characteristic or constant factor something that determines the limits of certain data values7
9655333705sampleA relatively small proportion of people who are chosen in a survey so as to be representative of the whole. a small part of a population that represents the whole A survey in star city representing the entire state of arkansas8
9655333706randomAssigning participants to experimental and control conditions by chance, thus minimizing preexisting differences between those assigned to the different groups. Assigning subjects to expenrimental groups based on chance. pulling names or numbers out of a hat9
9655333707biasAny systematic failure of a sampling method to represent its population Any way that tampers with the accuracy of the sample10
9655333708UndercoverageA sampling scheme that biases the sample in a way that gives a part of the population less representation than it has in the population. When some groups in the population are left out of the process of choosing the sample11
9655333709nonresponsebias introduced to a sample when a large fraction of those sampled fails to respond When many people of a sample do not respond12
9655333710voluntary response biasBias introduced to a sample when individuals can choose on their own whether to participate in the sample.13
9655333711statisticApplication of mathematics to describing and analyzing data14
9655333712independent(statistics) a variable whose values are independent of changes in the values of other variables15
9655333713historgramgraphical representation of a frequency distribution using vertical bars but bars touch each other to indicate variables are related16
9655333714box plotA dsiplay that shows the distribution of values in a data set seperated into four equal-sized groups. A box plot is constructed from the five number summary of the data.17
9655333715scatterplotA graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation).18
9655333716correlationA measure of the extent to which two factors vary together, and thus of how well either factor predicts the other. The correlation coefficient is the mathematical expression of the relationship, ranging from -1 to +119
9655333717skewnessThe extent to which cases are clustered more at one or the other end of the distribution of a quantitative variable rather than in a symmetric pattern around its center20
9655333718variencecommons measure of spread about the mean as center21
9655333719statistical significanceA statistical statement of how likely it is that an obtained result occurred by chance/The condition that exists when the probability that the observed findings are due to chance is very low22
9655333720P-valueA measure of statistical significance. The lower, the more likely the results of an experiment did not occur simply chance.23
9655333721empirical ruleThe rules gives the approximate % of observations w/in 1 standard deviation (68%), 2 standard deviations (95%) and 3 standard deviations (99.7%) of the mean when the histogram is well approx. by a normal curve24
9655333722lurking variableA variable that has an important effect on the relationship among the variables in a study but is not one of the explanatory variables studied25
9655333723null hypothesisHypothesis that predicts NO relationship between variables. The aim of research is to reject this hypothesis26
9655333724alternate hypothesis, is the hypothesis to be considered as an alternative to the null hypothesis. The null hypothesis will be rejected in favor of the Ha only if the sample data strongly indicate that the null hypothesis is false.27
9655333725quota sampleA sample deliberately constructed to reflect several of the major characteristics of a given population28
9655333726probabilityA number with a value from 0 to 1 that describes the likelihood that an event will occur. example, if a bag contains a red marble, a white marble and a blue marble then the probability of selecting a red marble is 1/3.29
9655333727descriptive statisticsMathematical procedures for organizing collections of data, such as determining the mean, the median, the range, the variance, and the correlation coefficient30
9655333728meanA measure of center in a set of numerical data, computed by adding the values in a list and then dividing by the number of values in the list.31
9655333729medianA measure of center in a set of numerical data. The median of a list of values is the value appearing at the center of a sorted version of the list - or the mean of the two central values if the list contains an even number of values.32
9655333730modeMeasure of central tendency that uses most frequently occurring score.33
9655333731rangeDistance between highest and lowest scores in a set of data.34
9655333732dataFacts and statistics collected together for reference or analysis35
9655333733Q1A location measure of the data such that has one fourth or 25% of the data is smaller than it. Found by dividing the ordered data set in half (excluding the middle observation if n is odd) and finding the median of the lower half of the data.36
9655333734Q3A location to measeure when counting data to such as the median where instead of counting 50% it is 75% from the beginning of the sorted data37
9655333735minimum(n.) the smallest possible amount; (adj.) the lowest permissible or possible38
9655333736outlierA value much greater or much less than the others in a data set39
9655333737margin of errorIn statistical research, the range of outcomes we expect for a population, given the data revealed by a sample drawn from that population40
9655333738statistical normalscoring the middle of the bell-curve; low, moderate, or high scoring41
9655333739simple random sampleA sample selected in such a way that every element in the population or sampling frame has an equal probability of being chosen. Equivalently, all samples of size n have an equal chance of being selected. A sample of size n selected from the population in such a way that each possible sample of size n has an equal chance of being selected.42
9655333740sampling distributionDistribution of sample proportions from sample to sample. A sampling distribution of a sample statistic for a fixed sample size n is the distribution of that statistic derived from every possible sample of size n for a given population. A distribution of statistics obtained by selecting all the possible samples of a specific size from a population43
9655333741stratified random sampleA method of sampling that involves dividing your population into homogeneous subgroups and taking a simple random sample in each subgroup. a sampling design in which the population is divided into several groups, and random samples are then drawn from each stratum44
9655333742systematic sampleA sample drawn by selecting individuals systematically from a sampling frame A sample drawn by selecting individuals systematically from a sampling frame. When there is no relationship between the order of the sampling frame and the variables of interest, a systematic sample can be representative.45
9655333743cluster sampleIs obtained by selecting all individuals within a randomly selected collection or group of individuals.46
965533374410% rulea sample has to be lass than 10% of the whole population47
9655333745InterpolationThe estimation of an unknown number between known numbers. Interpolation is a way of approximating price or yield using bond tables that do not give the net yield on every amount invested at every rate of interest and for every maturity.48
9655333746QualitativeData in the form of recorded descriptions rather than numerical measurements.49
9655333747theoretical probabilityA probability obtained by analyzing a situation. If all of the outcomes are equally likely, you can find the theoretical probability of an event by listing all of the possible outcomes and then finding the ratio of the number of outcomes producing the desired event to the total number of outcomes. For example, there are 36 possible equally likely outcomes (number pairs) when two fair number cubes are rolled. of these six have a sum of 7, so the probability of rolling a sum of 7 is 6/36 or 1/650
9655333803experimental probability51
9655333748block designThe subjects in an experiment are first divided into groups (called 'blocks') based on some common characteristic (such as gender) that is hypothesised to have an effect on the response. Randomization of treatments then happens within each block (each block is like its own mini-experiment)."52
9655333749blindingThe practice of concealing group assignment from study subjects, investigators, and/or those who assess subject outcomes, typically in the context of a randomized controlled trial. For ex, study subjects may receive capsules with identical appearance and taste; however, the treatment group receives the active drug, whereas the control group receives the placebo.53
9655333750double blindAn experiment in which neither the subjects nor the people who work with them know which treatment each subject is receiving Neither the subjects nor the people who have contact with them know which treatment a subject received54
9655333751placeboA fake treatment. A chemically inert substance that produces real medical benefits because the patient believes it will help her55
9655333752least squares regression linethe line with the smallest sum of squared residuals56
9655333753type I errorAn error that occurs when a researcher concludes that the independent variable had an effect on the dependent variable, when no such relation exists; a "false positive57
9655333754type II errorAn error that occurs when a researcher concludes that the independent variable had no effect on the dependent variable, when in truth it did; a "false negative58
9655333804joint frequency59
9655333755matched pairsan observational technique that involves matching each participant in the experimental group with a specific participant in the control group in order to eliminate the possibility that a third variable (and not the independent variable) caused changes in the dependent variable60
9655333756conditional prababilityprobability given that something else has already occurred61
9655333757sample spaceSet of all possible outcomes of an experiment62
9655333758confounded variableA variable whose effect on the response variable cannot be separated from the effect of the explanatory variable on the response variable. (Note: Usually confounded variables are lurking variables but only a few lurking variables are also confounded.)63
9655333759marginal frequencyA set of intervals, usually adjacent and of equal width, into which the range of a statistical distribution is divided, each associated with a frequency indicating the number of measurements in that interval.64
9655333760coefficient of determinationThe statistic or number determined by squaring the correlation coefficient. Represents the amount of variance accounted for by that correlation. Statistic that represents amount of variance accounted for by a correlation.65
9655333761binomialA two-name naming system.66
9655333762unimodalhaving one mode; this is a useful term for describing the shape of a histogram when it's generally mound-shaped a data set with one mode such a normal distribution usually has only one mode67
9655333763bimodalA type of distribution, where there is two or more categories with an equal count or cases and with more cases than the other categories. A distribution with two modes68
9655333764experimentA kind of research in which the researcher controls all the conditions and directly manipulates the conditions, including the independent variable. Testing the hypothesis69
9655333765law of large numbers(statistics) law stating that a large number of items taken at random from a population will (on the average) have the population statistics70
9655333766extrapolationcalculation of the value of a function outside the range of known values71
9655333767snowballHuyen wanted to conduct market research to find out why students were unhappy with Marketing 431, probably the finest course ever to be offered by a university. In order to do this she needed to find people who were unhappy with the course. Figuring that these people would talk to each other, she used a sampling technique where she found one person who was unhappy with the course and, after asking her research questions, asked this person for the name of another person who was unhappy with the course.72
9655333768IQRA measure of variability, based on dividing a data set into quartiles Difference between upper and lower quartile of a boxplot73
9655333769Confidence intervalA range of values for a variable of interest; the specified probability is called the confidence level and the end points of the confidence interval are called the confidence limits A range of numbers in which most of the data values are likely to fall. we are 95% confident that etc.74
9655333770Standard ErrorA statistic providing an estimate of the possible magnitude to error. The larger the standard error of measurement, the less reliable the score. Standard deviation of sampling distribution75
9655333805Residual76
9655333771Convenience sampleWhenever a sample is taken it gives an improper results because the sample was taken from a very convenient area instead of representing a population77
9655333772simulationA representation of a situation or problem with a similar but simpler model or a more easily manipulated model in order to determine experimental results.78
9655333773degrees of freedomThe number of individual scores that can vary without changing the sample mean. Statistically written as 'N-1' where N represents the number of subjects.79
9655333774two way tableA table containing counts for two categorical variables. It has r rows and c columns. describes to categorical variables with row variable and column variable80
9655333775spreadThe visible variation in a sample distribution81
9655333776centerThe measure of the distance the mode is from the center of a distribution82
9655333806shape83
9655333807discrete random variable84
9655333808central limit theorem85
9655333809standardized value86
9655333810mutually exclusive87
9655333777wording biasWhenever a bias is created in a sample by the way the survey is worded to favor one question88
9655333811causation89
9655333812z test90
9655333813t test91
9655333778chi squared goodness of fittests how well close the observes data is to what would be expected under the model. If a sign diff is found b/w the two then ob. data has not been generated by chance. nominal data Determine if scores from one variable match expectations for that distribution a gambler placed $1,000 into a game of greed in which he lost. He hopes to catch his opponent and bust him for loading the dice. He does this by choosing one dice to roll 36 times. He knows that the each side has an equal chance of landing face up. He hopes to get an outcome abnormal to this. Given the data below, can we prove that the dice are loaded92
9655333779frequency tableA grouping of qualitative data into mutually exclusive classes showing the number of observations in each class. A chart showing the number of times a specific event happens.93
9655333780area principlethe area occupied by a part of the graph should correspond to the magnitude of the value it represents94
9655333814simpsons paradox95
9655333781contingency tabledisplays counts, and, sometimes, percentages of individuals falling into named categories on two or more variables. The table categorizes the individuals on all variables at once, to reveal possible patterns in one variable that may be contingent on the category of the other. A two-variable table with cross-tabulated data.96
9655333782stem and leaf displayA multiple column table depicting the individual digits of the scores. A score of 95 would have a stem of 9 and a leaf of 5, a score of 62 would have a stem of 6 and a leaf of 2. If a particular stem has more than one leaf, such as the scores 54, 58, and 51, the stem of 5 has three leaves, in this case 458. . It shows the range of values of the variable97
9655333783multimodalDescribes a graph of quantitative data with more than two clear peaks. A distribution with more than two modes98
9655333784uniformA histogram doesn't appear to have any mode and in which all the bars are approximately the same height Evenly spaced99
9655333785symetricWhen in a normal distribution both sides are identical100
9655333786time plotDisplays data that change over time. Often, successive values are connected with lines to show trends more clearly. Sometimes a smooth curve is added to the plot to help show long-term patterns and trends. Displays data that change over time.101
9655333787sestandard deviation of residuals102
9655333788r2overall measure of how successful the regression is in linearlly relating to y and x103
9655333815leverage104
9655333789influential pointa point when omitted will give very different results105
9655333790censusWhen a survey has no sample but instead test or surveys the entire population106
9655333816multistage samole107
9655333791pilotsmall trial run of a survey to see if questions are clear108
9655333792convenience sampleChoosing a sample because it is convenient. failing to get a proper representation of the population because If you survey everyone on your soccer team who attends tonight's practice, you are surveying a convenience sample.109
9655333793response biasAnything in a survey design that influences responses falls under the heading of response bias. One typical response bias arises from the wording of questions, which may suggest a favored response. Voters, for example, are more likely to express support of "the president" than support of the particular person holding that office at the moment. Anything that changes the response in a survey A police officer asking teenagers about drug use110
9655333794observational studyA study based on data in which no manipulation of factors has been employed. A study that observes characteristics of an existing population. usually a survey111
9655333795retrospective studyWhat study examines whether a past association exists between an exposure of interest and development of a present condition? data are collected from the past by going back in time112
9655333796prospective studyan observational study in which subjects are followed to observe future outcomes113
9655333797statistic factorA multifactor model in which statistical methods are applied ot a set of historical returns to determine portfolios that best explain either historical return covariances or variances.114
9655333798control groupIn an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.115
9655333799blindingThe practice of concealing group assignment from study subjects, investigators, and/or those who assess subject outcomes, typically in the context of a randomized controlled trial. For ex, study subjects may receive capsules with identical appearance and taste; however, the treatment group receives the active drug, whereas the control group receives the placebo.116
9655333800placebo effectExperimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which is assumed to be an active agent.117
9655333801trialA performed experiment based upon the hypothesis you made.118
9655333802maximum(n.) the greatest possible amount or degree in a data sample the largest value in a set of data119

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