# Test 3

 Statistics a branch of mathematics that involves the collection, analysis, and interpretation of data. Descriptive Statistics summarize any set of numbers so you can understand and talk about them more intelligibly. Inferential Statistics is used to analyze the data after they had conducted an experiment to determine whether the IV had a significant effect Measures of Central Tendency one of the essential characteristics of the typical or representative score. Measurement an assignment of symbols to events according to a set of rules.exp. your grade on a test is a symbol that stand for you performance. Scale of Measurement a particular set for rules used in assigning a symbol to the event in question.Nominal ScaleOrdinal ScaleInterval Scale Nominal Scale A scale of measurement in which events are assigned to categories.Exp. Furniture: Chair, Desk, Bed,Fruit: Pineapple, Watermelon, Peach Ordinal Scale A scale of measurement that permits events to be rank ordered.Exp: First, Second, Third, Fourth Interval Scale A scale of measurement that permits rank ordering of events with the assumption of equal intervals between adjacent events.DOES NOT HAVE A TRUE ZERO.Exp. Temperature: 1 degree, 2 degrees: 0 degrees does not mean no temp.Scores on a SAT test: scoring 0 on verbal subtest does not mean no verbal skills. Ratio Scale A scale of measurement that permits rank ordering of events with the assumptions of equal intervals between adjacent events and a true zero point. Mode the score in a distribution that occurs most often.12, 15, 20, 20, 20Mode = 20 Median the number that divides a distribution in half.First you must rank order the numbers.Exp. 56, 15, 12, 20, 17 -----> 12, 15, 17, 20, 56Median = 17 Mean is the arithmetic average of a set of numbers; found by adding all the scores in a set and then dividing the nymber of scores.Exp: 12, 15, 18, 19, 16 -----> 12+15+18+19+16 = 80 -----> 80/5= 16Mean = 16 Pie Chart Graphical representation of the percentage allocated to each alternative as a slice of a circular pie. Histogram a graph in which the frequency for each category of quantitative variable is represented as a vertical column that touches the adjacent column Range a measure of variability that is computed by subtraction the smallest score from the largest score.Exp. 1, 1, 1, 1, 5, 6, 6, 8, 25 ------> 25 - 1 = 24Range: 24 Variance a single number that represents the total amount of variation in a distribution; also the square of the standard deviation. Standard deviation scuare root of the variance Normal distribution a symmetrical, bell- shaped distribution having half the scores above the mean and half the scores below the mean. The number that occurs most frequently mode A_______ presents data in terms of frequencies per category. histogram The ______ is a single number that represent she total amount of variability in a distribution. Variance Correlation Coefficient A single number representing the degree of relation between two variables. Null hypothesis a hypothesis that says that all differences between groups are due to chance. t test the inferential statistical test used to evaluate the difference between two means. Degrees of freedom the ability of a number in a specified set to assume andy value df = (Na-1)+(Nb-1) If students wear dressy clothes to the shopping mall, then the time it takes a salesperson to offer to serve them will be shorter then the latency to service for students dressed in sloppy. One-tail, directional hypothesis One tail evaluates the probability of only one possible outcomedirectional hypothesis An experimental hypothesis my be incorrectly REJECTED. Type II error An experimental hypothesis my be incorrectly ACCEPTED. Type I error Type 1 error Accepting the experimental hypothesis when the null hypothesis is true Type II error\ Accepting the null hypothesis when the experimental hypothesis is true. Effect size The magnitude of size of the experimental treatment. The one-tail test of significance is associated with a directional hypothesis The Type I error is under the direct control of the experimenter If yo could compare all men and women in the world, you would grind that men are significantly more aggression between men and women. You have made a type II error Experimental design the general plan for selection plan for selection participants, assigning participants to experimental conditions, controlling extraneous variables, and gathering data. Principle of parisimony the belief that explanations of phenomena and events should remain simple until the simple explanations are no longer valid.Exp. Don't needlessly complicate the question that you are asking.Two group design in the most parsimonious The least amount of groups in a simple single IV experiment? twoControl Group and Experimental Group Independent Variable (IV) A stimulus or aspect of the environment that the experimenter directly manipulates to determine its influences on behavior. Dependent Variable A response or behavior that the experimenter measures. Changes in DV should be caused by manipulation of the Independent variable. Extraneous Variables Uncontrolled variables that may unintentionally influences the dependent variable (DV) and thus invalidate an experiment. Levels Differing amounts or types of an IV used in an experiment (also known as treatment conditions) If the probability of the result occurring by chance is less then .05 what can be concluded? the two groups differ significantly Experimental group in two-group design, the group of participants that does not receive the IV. Random Assignment a method of assigning research participants of groups that each participants to groups so that each participants has an equal chance of being in any group. Random Selection a control techniques that ensures that each member of the the population has an equal chance of being chosen for an experiment. Independent Groups Groups of participants formed by random assignment. Between-Subjects comparison refers to a contrast between groups of participants how were randomly. Confounded Experiment and experiment in which an extraneous variable varies systematically with the IV, which makes drawing a cause-and-effect relation impossible. Correlated Assignment A method of assigning research participants to groups so that there is a relationship between small numbers of participants; these small groups are then randomly assigned to treatment conditions Matched Pairs Research participants in two-group design who are measured and equated on some variable before experiment. Repeated measures an experimental procedures in which research participants are tested or measured more than once. Natural Pairs research participants in two-group design who are naturally related in some way Within-subjects comparison refers to a contras between groups of participants who were assigned to groups through matched pairs natural pairs, natural pairs, or repeated measures The differing amounts of you IV are known as the _____ of the IV. levels Flipping a coin is an example of what type of assignment Random Assignment Brother and sister is an example of what type of pair natural pairs take the same test each month repeated measures two people with the same IQ matched pairs Random assignment is more likely to create equal groups when large samples are involved Between-groups variability variability in DV scores that is due to the effects of the IV. Error Variability Variability in DV scores that is due to factors other than the IV, such as individual differences, measurement error, and extraneous variation.aka within-groups variability Degrees of freedom the ability of a number in a specified set to assume any value True Experiment an experiment in which the experimenter directly manipulates the IV. Ex Po Facto Research a research approach in which the experimenter cannot directly manipulate the IV but can only classify, categorize, or measure the IV because it is predetermined in the participants.Exp. IV = sex male or female Homogeneity of Variance the assumption that the variance are equal for the two (or more) groups you plan to compare statistically.Exp. .222 well above .05 the variability of the scores of the two groups is similar. Heterogeneity of Variance Occurs when we do not have homogeneity of variance; this means that our two (or more) groups' variances are not equivalent.If p value is less then .05 the variability of the scores were not comparable Robust refers to the statistical test that can tolerate violation of its assumption and still yield valid results. Positive Correlation As scores on on e variable increase, scores on the second variable also increase Negative correlation as scores on one variable increase, scores on the second variable decrease. Compared to the t test for independent groups, the t test for correlated samples________ degrees of freedom. fewer If the variability of our two groups is similar, we have______; if the variability of the groups is dissimilar, we have_______. When we write a report of our experimental results, we explain the results in_______ and _______. words and numbers Experimental Design the general plan for selecting participants, assigning participants to experimental conditions, controlling extraneous variables, and gathering data. Independent Variables (IV) a stimulus or aspect of the environment that the experimenter directly manipulates to determine its influence on behavior. Principle of Parisimony the belief that explanations of phenomena and events should remain simple until the simple explanations are no longer valid. Levels differing amounts or types of an IV used in an experiment.(also known as treatment conditions) Treatment Groups groups of participants that receive the IV Independent Groups groups of participants formed by random assignment Correlated Groups Groups of participant formed by matching, natural pairs, or repeated measures. Random Assignment a method of assigning research participants to groups so that each participant has an equal chance of being in any group Control Procedure one of several steps experimenters take to ensure that potential extraneous variables are controlled, including random assignment matching, and so on Confounded Experiment An experiment in which an extraneous variable varies systematically with the IV, which makes drawing a cause-and-effect relation impossible. Matching Variables a potential extraneous variable on which we measured our research participants and from which we form sets of participants who are equal on the variable. Placebo Effect an experimental effect caused by expectation or suggestion rather than the IV. Expo Facto Research a research approach in which the experimenter cannot directly manipulate the IV but can only classify categorize, or measure the IV because it is predetermined in the participants. Exp. Sex, male or female The simplest possible multiple- group would have _____ and _____ treatment groups. 1 and 3 One-way ANOVA a statistical test used to analyze data from an experimental design with one independent variable that has three or more groups (levels) Completely Randomized ANOVA This one-way ANOVA uses independent groups of participants. Repeated-measures ANOVA this one-way ANOVA uses correlated groups of participants. Operational Definition defining the independent dependent, and extraneous variables in terms of the operations needed to produce them. Between-groups variability variability in DV scores that is due to the effects of the IV Error Variability variability in DV scores that is due to factors other than the IV, such as individual differences, measurement error and extraneous variation (also known as within-groups variability) Within-groups Variability another term for error variability. Source table a table that contains the results of ANOVA. Sources refers to the source of the different types of variation Sum of Squares the amount of variability in the DV attributable to each source Mean Square the "averaged" variability for each source; computed by dividing each source's sum of squares by its degrees of freedom. Variance a single number that represents the total amount of variation in distribution; also the square of the standard deviation. Post hoc comparison statistical comparison made between group means after fining a significant F ratio. A zero correlation indicates that changes in one variable are not systematically related to changes in the other variable. Matthew not passing his test has nothing to do with Paul not passing his test AuthorLEGZ08 ID47749 Card SetTest 3 DescriptionStatistics and Data Updated2010-11-08T06:03:34Z Show Answers