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AP Statistics Midterm Review Flashcards

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78813876095 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
7881387610z 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
7881387611standard 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
7881387612population(statistics) the entire aggregation of items from which samples can be drawn What the sample in an experiment or study usually reperesents3
7881387613categorical 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
7881387614quantitative 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
7881387615bar 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
7881387617sampleA 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 arkansas7
7881387618randomAssigning 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 hat8
7881387619biasAny systematic failure of a sampling method to represent its population Any way that tampers with the accuracy of the sample9
7881387620UndercoverageA 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 sample10
7881387621nonresponsebias introduced to a sample when a large fraction of those sampled fails to respond When many people of a sample do not respond11
7881387622voluntary response biasBias introduced to a sample when individuals can choose on their own whether to participate in the sample.12
7881387623statisticApplication of mathematics to describing and analyzing data13
7881387624independent(statistics) a variable whose values are independent of changes in the values of other variables14
7881387625historgramgraphical representation of a frequency distribution using vertical bars but bars touch each other to indicate variables are related15
7881387626box 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.16
7881387627scatterplotA 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).17
7881387628correlationA 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 +118
7881387629skewnessThe 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 center19
7881387630variencecommons measure of spread about the mean as center, standard deviation squared20
7881387631statistical 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 low21
7881387633empirical 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 curve22
7881387634lurking variableA variable that has an important effect on the relationship among the variables in a study but is not one of the explanatory variables studied23
7881387638probabilityA 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 1/3.24
7881387639descriptive statisticsMathematical procedures for organizing collections of data, such as determining the mean, the median, the range, the variance, and the correlation coefficient25
7881387640meanA 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.26
7881387641medianA 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.27
7881387642modeMeasure of central tendency that uses most frequently occurring score.28
7881387643rangeDistance between highest and lowest scores in a set of data.29
7881387644dataFacts and statistics collected together for reference or analysis30
7881387645Q1A 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.31
7881387646Q3A 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 data32
7881387647minimum(n.) the smallest possible amount; (adj.) the lowest permissible or possible33
7881387648outlierA value much greater or much less than the others in a data set34
7881387650statistical normalscoring the middle of the bell-curve; low, moderate, or high scoring35
7881387651simple 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.36
7881387653stratified 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 stratum37
7881387654systematic 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.38
7881387655cluster sampleIs obtained by selecting all individuals within a randomly selected collection or group of individuals.39
788138765610% rulea sample has to be less than 10% of the whole population40
7881387657InterpolationThe 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.41
7881387658QualitativeData in the form of recorded descriptions rather than numerical measurements.42
7881387659theoretical 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 1/643
7881387661block 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)."44
7881387662blindingThe 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.45
7881387663double 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 received46
7881387664placeboA fake treatment. A chemically inert substance that produces real medical benefits because the patient believes it will help her47
7881387665least squares regression linethe line with the smallest sum of squared residuals48
7881387669matched 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 variable49
7881387670conditional prababilityprobability given that something else has already occurred50
7881387671sample spaceSet of all possible outcomes of an experiment51
7881387672confounded 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.)52
7881387673marginal 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.53
7881387674coefficient 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.54
7881387676unimodalhaving 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 mode55
7881387677bimodalA 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 modes56
7881387678experimentA kind of research in which the researcher controls all the conditions and directly manipulates the conditions, including the independent variable. Testing the hypothesis57
7881387680extrapolationcalculation of the value of a function outside the range of known values58
7881387682IQRA measure of variability, based on dividing a data set into quartiles Difference between upper and lower quartile of a boxplot59
7881387685Residualobserved value - predicted value60
7881387686Convenience sampleWhenever a sample is taken it gives an improper results because the sample was taken from a very convenient area instead of representing a population61
7881387687simulationA representation of a situation or problem with a similar but simpler model or a more easily manipulated model in order to determine experimental results.62
7881387689two 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 variable63
7881387690spreadThe visible variation in a sample distribution64
7881387691centerThe measure of the distance the mode is from the center of a distribution65
7881387692shape66
7881387693discrete random variablea random variable that can take one of a finite number of distinct outcomes67
7881387695standardized valueThe z-score obtained from standardizing an x-value.68
7881387696mutually exclusiveEvents that cannot occur at the same time.69
7881387697wording biasWhenever a bias is created in a sample by the way the survey is worded to favor one question70
7881387698causationA cause and effect relationship in which one variable controls the changes in another variable.71
7881387702frequency 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.72
7881387706stem 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 variable73
7881387707multimodalDescribes a graph of quantitative data with more than two clear peaks. A distribution with more than two modes74
7881387708uniformA histogram doesn't appear to have any mode and in which all the bars are approximately the same height Evenly spaced75
7881387709symmetricWhen in a normal distribution both sides are identical76
7881387711sestandard deviation of residuals77
7881387712r^2overall measure of how successful the regression is in linearlly relating to y and x78
7881387714influential pointan observation that when removed would markedly change the LSRL79
7881387715censusWhen a survey has no sample but instead tests or surveys the entire population80
7881387716multistage samplea sampling design where several sampling methods are combined81
7881387718convenience 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.82
7881387719response 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 use83
7881387720observational 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 survey84
7881387724control 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.85
7881387725blindingThe 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.86
7881387726placebo 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.87
7881387727trialeach repetition or observation of an experiment88

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