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AP Statistics Vocabulary Flashcards

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98785296725 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
9878529673z 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
9878529674standard 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
9878529675population(statistics) the entire aggregation of items from which samples can be drawn What the sample in an experiment or study usually reperesents3
9878529676categorical 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
9878529677quantitative 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
9878529678bar 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
9878529679parameter(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
9878529680sampleA 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
9878529681randomAssigning 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
9878529682biasAny systematic failure of a sampling method to represent its population Any way that tampers with the accuracy of the sample10
9878529683UndercoverageA 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
9878529684nonresponsebias introduced to a sample when a large fraction of those sampled fails to respond When many people of a sample do not respond12
9878529685voluntary response biasBias introduced to a sample when individuals can choose on their own whether to participate in the sample.13
9878529686statisticApplication of mathematics to describing and analyzing data14
9878529687independent(statistics) a variable whose values are independent of changes in the values of other variables15
9878529688historgramgraphical representation of a frequency distribution using vertical bars but bars touch each other to indicate variables are related16
9878529689box 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
9878529690scatterplotA 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
9878529691correlationA 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
9878529692skewnessThe 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
9878529693variancecommons measure of spread about the mean as the center21
9878529694statistical 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
9878529695P-valueA measure of statistical significance. The lower, the more likely the results of an experiment did not occur simply by chance.23
9878529696empirical 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
9878529697lurking 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
9878529698null hypothesisHypothesis that predicts NO relationship between variables. The aim of research is to reject this hypothesis26
9878529699alternate 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
9878529700probabilityA 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 1/3.28
9878529701descriptive statisticsMathematical procedures for organizing collections of data, such as determining the mean, the median, the range, the variance, and the correlation coefficient29
9878529702meanA 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.30
9878529703medianA 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.31
9878529704modeMeasure of central tendency that uses most frequently occurring score.32
9878529705rangeDistance between highest and lowest scores in a set of data.33
9878529706dataFacts and statistics collected together for reference or analysis34
9878529707Q1A 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.35
9878529708Q3A 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 data36
9878529709minimum(n.) the smallest possible amount; (adj.) the lowest permissible or possible37
9878529710outlierA value much greater or much less than the others in a data set38
9878529711margin of errorIn statistical research, the range of outcomes we expect for a population, given the data revealed by a sample drawn from that population39
9878529712simple 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.40
9878529713sampling 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 population41
9878529714stratified 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 stratum42
9878529715systematic 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.43
9878529716cluster sampleIs obtained by selecting all individuals within a randomly selected collection or group of individuals.44
987852971710% rulea sample has to be lass than 10% of the whole population45
9878529718InterpolationThe 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.46
9878529719QualitativeData in the form of recorded descriptions rather than numerical measurements.47
9878529720theoretical 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 1/648
9878529721experimental probabilityProbability obtained by simulation or observing phenomena in real life49
9878529722block 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)."50
9878529723blindingThe 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.51
9878529724double 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 received52
9878529725placeboA fake treatment. A chemically inert substance that produces real medical benefits because the patient believes it will help her53
9878529726least squares regression linethe line with the smallest sum of squared residuals54
9878529727type 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 positive", sending an innocent person to jail, rejecting the null when in fact it is true.55
9878529728type 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 negative", letting a guilty man go free, failing to reject the null when it is false.56
9878529730matched 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 variable57
9878529731conditional prababilityprobability given that something else has already occurred58
9878529732sample spaceSet of all possible outcomes of an experiment59
9878529733confounded 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.)60
9878529734marginal 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. (found in the margins of a two way table)61
9878529735coefficient 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.62
9878529737unimodalhaving 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 mode63
9878529738bimodalA 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 modes64
9878529739experimentA kind of research in which the researcher controls all the conditions and directly manipulates the conditions, including the independent variable. Testing the hypothesis65
9878529740law 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 statistics66
9878529741extrapolationcalculation of the value of a function outside the range of known values67
9878529742IQRA measure of variability, based on dividing a data set into quartiles Difference between upper and lower quartile of a boxplot68
9878529743Confidence 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.69
9878529744Standard 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 distribution70
9878529745Residualdistance an estimate is from the actual/observed value. residual = observed - expected71
9878529746Convenience sampleWhenever a sample is taken it gives an improper results because the sample was taken from a very convenient area instead of representing a population72
9878529747simulationA representation of a situation or problem with a similar but simpler model or a more easily manipulated model in order to determine experimental results.73
9878529748degrees 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.74
9878529749two 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 variable75
9878529750spreadThe visible variation in a sample distribution76
9878529752shapegeneral form of a distribution77
9878529753discrete random variableone that can be counted on a finite spectrum78
9878529754central limit theoremA distribution will become approximately normal as sample size increases79
9878529755standardized valuez score or t score which makes values comparable among multiple data sets80
9878529756mutually exclusivecannot happen together81
9878529758causationone event enables another to occur82
9878529759z testused for normal distributions to determine if a result is significantly significant, if the observed results are likely not to be from chance.83
9878529760t testused for a t distribution to determine if results are statistically significant, if the observed results are likely not to be from chance.84
9878529761chi 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 loaded85
9878529762frequency 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.86
9878529763stem 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 variable87
9878529765uniformA histogram doesn't appear to have any mode and in which all the bars are approximately the same height Evenly spaced88
9878529766symmetricWhen in a normal distribution both sides are identical89
9878529767"Se"standard deviation of residuals90
9878529768r2overall measure of how successful the regression is in linearlly relating to y and x91
9878529769influential pointa point when omitted will give very different results92
9878529770censusWhen a survey has no sample but instead test or surveys the entire population93
9878529772convenience 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.94
9878529773response 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 use95
9878529774observational 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 survey96
9878529775retrospective 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 time97
9878529776prospective studyan observational study in which subjects are followed to observe future outcomes98
9878529777control 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.99
9878529778blindingThe 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.100
9878529779placebo 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.101
9878529780trialA performed experiment based upon the hypothesis you made.102
9878529781maximum(n.) the greatest possible amount or degree in a data sample the largest value in a set of data103

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