AP Statistics 9 Flashcards

Terms Definitions
 bimodal distributions with two modes comparing distributions use back-to-back stem, or histogram/dot with same scale and compare their shape, center, and spread sample a representative subset of a population, examined in hope of learning about the population level the experimental values that are chosen for each factor distribution describes how a quantitative variable behaves. Generally include shape, center, spread, & unusual features. undercoverage some portion of the intended population is either unrepresented or under-represented range the maximum data value minus the minimum data value histogram a display for quantitative data that uses adjacent bars to represent counts or percentages of values falling in each interval principles of experimental design control, randomize, replicate, block outliers values that fall outside the overall pattern of the data multistage sampling sampling schemes that combine several different sampling methods at different stages sample statistics mathematical measures taken from a sample of the population of interest like the sample mean and sample standard deviation variance the standard deviation squared, it is a measure of spread Confidence Interval Used to estimate the population parameter; an interval within which we believe lays the TRUE population parameter. bar chart a display for categorical data that uses bar height to represent counts or percentages for each category frequency table lists the categories for a categorical variable and displays the counts for each category statistic a number that describes the data; it can be a measure of center or spread 5 number summary includes the minimum, first quartile, median, third quartile, & the maximum response bias anything in the survey design that influences the responses from the sample P-value The chance of getting the results if the null hypothesis is true. cluster sample population is split into parts or clusters usually based on geography and then entire clusters are selected randomly and sampled Theoretical Probability The proportion of times the outcome would occur in a very long series of repetitions (determined mathematically). placebo a fake treatment often given to the control group to help prevent the placebo effect (subjects improving by the power of suggestion) simple random sample abbreviated SRS, this requires that every item in the population has an equal chance to be chosen and that every possible combination of items has an equal chance to exist. No grouping can be involved. stratified random sample population is divided into homogenous groups and then a random sample is drawn from each group nonresponse bias bias created when people who are randomly selected refuse to particiapte in the sample quantitative variable where the data collected is numerical and it makes sense to use it for numerical operations measures of center mean for distributions that are symmetric, median for all other distribution shapes modified boxplot a display for quantitative data that graphs the five-number summary on an axis and shows outliers of they exist Interquartile Range (IQR) the third quartile minus the first quartile dotplot a display for either kind of data that uses a dot to represent each individual in the data set double blind when the subjects as well as those evaluating the result of an experiment do not know which subjects are in the treatment or control groups single blind when the subjects in an experiment do not know if they are in the treatment or control group Probability Model a list of all possible outcomes and the probability of each Central Limit Theorem The sampling distribution of a large sample will be approximately normal even if the population is not normal. Statistically significant When the p-value is lowp; not likely to happen by chance is the null hupothesis is true. Empirical Probability The number of times an outcome occurs in a set of trials that are actually performed (used as an estimate of the theoretical probability). median the value in the center of an ordered data set relative frequency table lists the categories for a categorical variable and displays the percenatges for each category outlier formula less than Q1 - 1.5 (IQR) more than Q3 + 1.5 (IQR) Sample Space a list of all possible outcomes of a random phenomenon S= {...........} first quartile the value where 25 % of the data fall below it in an ordered list
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