stats glossary

stats glossary - GLOSSARY alternative hypothesis: A...

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GLOSSARY alternative hypothesis: A statement about the value of a parameter that is either “less than,” “greater than,” or “not equal to” a hypothesized number or another parameter; the hypothesis that the researcher usually wants to prove or verify. Analysis of Variance (ANOVA): A procedure used to test equality of three or more means. approximate sampling distribution : The distribution of -values obtained from repeatedly taking x simple random samples of the same size from the same population. (An is computed from each x sample.) approximate t test: A test for comparing the means of two independent samples or two treatments where the test statistic has an approximate t distribution. This is the preferred two sample t test, but it requires statistical software. association: For quantitative data, large values of one variable tend to occur with large (or small) values of another variable. For categorical data, certain responses for one variable tend to occur with certain responses of the other variable. association vs. causation : We can only argue causation from association if the results having significant association are from an experiment. bar graph: A graphical representation of categorical data. Names of each category are listed on the x axis and a bar that has height representing the frequency (or percentage) in that category is place over each category name. bias (sampling): A condition that occurs when the design of a study systematically favors certain outcomes. bivariate data: Two measurements are made on each unit. block: A group of experimental units sharing some common characteristic. In a randomized complete block design, random allocation of treatments is carried out separately within each group. boxplot: A plot of data that incorporates the maximum observation, the minimum observation, the first quartile, the second quartile (median) and the third quartile. categorical (or qualitative) variable: A variable that can be classified into groups or categories such as gender and religion. causation: Changes in the explanatory variable directly affect the response variable. Experiments are needed to verify causation. census: The enumeration of every unit in a population. center: A summary number about which observations tend to cluster. Measures of center include the mean and the median.
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center line: The middle line on a control chart. Its value is the target value of the mean when the process is in control. Central Limit Theorem (CLT): The name of the theorem stating that the sampling distribution of a statistic (e.g. ) is approximately normal whenever the sample is large and random. x Chi-distribution: The theoretical distribution that models the test statistic for doing Chi-Square tests. Chi-square test statistic: A test statistic computed from data that has an approximate chi-square distribution.
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This test prep was uploaded on 04/16/2008 for the course STAT 221 taught by Professor Collings during the Winter '08 term at BYU.

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stats glossary - GLOSSARY alternative hypothesis: A...

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