EXSC 520- Quiz 2 with Verified Solutions Fully Solved

EXSC 520- Quiz 2 with Verified Solutions Fully Solved Correlation background - Answers Is used to quantify the degree of relationship, or association, between 2 variables. Curvilinear - Answers Plot of bivariate data where the best fit line is not straight. Is a measure of linear relationship. The curved line represents the relationship between assumed by pearson's coefficient. The true relationship is curvilinear and strong. Bivariate Regression background - Answers Regression analysis applied to one independent variable and one dependent variable.(simple linear progression). Standard deviation residuals - Answers The vertical distance from any point in a scatter diagram to the line of the best fit. Bivariate regression residuals, - Answers The vertical distance to any point to the line. Standard error of the estimate - Answers a numerical value that indicates the amount of error in prediction of a Y value in a bivariate or multivariate regression. Interpreted as the standard deviation of the errors, or residuals, made when predicting Y from X. homoscedasticity - Answers an assumption of parametric inferential statistics is that the data are normally distributed. a further assumption of regression analysis is called Multiple regression background - Answers Regression analysis applied to more than one independent variables(X1,2,3) and one dependent variable(Y). Muticolinearity - Answers A condition in which two or more independent variables in multiple regression are highly correlated with each other. It leads to 2 correlated problems. Variance inflation factor - Answers (VIF), an index of extent of multicollinearity in a data set . Indices that help us to calculate quantify the amount of multicollinearity in the data. Tolerance - Answers The denominator of the variance inflation factor(VIF). T TEST, - Answers we compare a single sample mean against the mean from a known population value. It is the technique by which we perform this analysis. The T test is useful for conducting experimental research. The t test may be modified to make comparison between observed proportions (pag 172). INDEPENDENT TEST, - Answers in which we compare the means from two independent samples. DEPENDENT T TEST, - Answers in which two means that come from correlated samples are compared. Assumptions of t-test - Answers If the assumption are met the T test is valid and can be applied. We can say the the T TEST is QUIET ROBUST when is produces reasonably reliable results, even if the assumptions are not met totally. Homogenity of variance. - Answers Equality of variances among a set of two or more measures. (it is an assumption). Parametric and non parametric. - Answers Parametric when data that meet the assumptions of normality. Independent t-test - Answers Independent, a test performed to compare the means from two independent samples. Typically each sample is from a different group of subjects. Effect size - Answers An estimate of the percent of total variance between means that can be attribuated to the result of treatment. A measurement of a the magnitude of the difference two mean values independent of sample sizes. A measurement of the magnitude of association between variables. Power - Answers The ability of a test to correctly reject a false null hypothesis. It is the ability of a test to detect a real effect in a population based on a sample taken from that population. It is the probability of correctly rejecting the null hypothesis when it is false. ANOVA - Answers is the analysis of variance, an F value that represents the ratio of between group and withing group variance . the ANOVA is a parametric statistical technique used to determine wheter significant differences exist among means from 3 or more sets of sample DATA. The analysis of variance examines differences between the means of 3 or more groups by comparing the variability between the group means with the variability of scores within the groups. F ratio, - Answers is the ratio of the average between group variances should be divided by the average within-group variance, is expected to be about 1.00. when the value of F ratio exceeds 1.00 by more than would be expected by chance alone, the variance between the means is judged to be significant and H0 is rejected. ANOVA Assumptions - Answers the population from which the samples are drawn is normally distributed. Even when is not normally distributed is considered to be robust. 2) as a general rule, the largest group variance should not be more than two times the smallest group variance. The variability of the samples in the experiment is equal or nearly so(homogeneity of variance). 3)the scores in all groups are independent, the scores in each group are not dependent on, or correlated with. ETA squared - Answers A measure of effect size in analysis of variance, same as R2. Repeated-measure ANOVA - Answers Measuring the same subjects more once, as in pre post comparison. Same as within subjects design. Greenhouse geisser - Answers A conservative adjustment to the degrees of freedom in repeated measures analysis of variance to correct for violation of the assumption of sphericity. Interclass correlation - Answers A method of determining relative reliability (Until less), using mean square terms from repeated measures analysis of variance. It may be used on two or more repeated measures. It is sensitive to the degree of between-subjects variability in the data such that, all else being equal. Interclass correlation permits to quantify the reability coefficient is formally quantified. Standard error of measurement - Answers An absolute index of reliability of a test(units are the same as the units of the variable). Can be used to construct confidence intervals about individual scores and about individual change scores. It is and index that reflexes the degree of absolute measurement error. It is in units of the dependent variable and it is not sensitive to the characteristics of the population from which the sample data were drawn. POST HOC - Answers after the fact, when a significant F is found, the post hoc tests must be performed to identify the group or groups that differ. Background of nonparametric statistics - Answers Data that do not meet the assumption of normality. Mann-Whitney U - Answers A non parametric statistical tecqnique for determining the significance of the difference between rankings of two groups of subjects who have been ranked on the same variable. Kruskal-Wallis - Answers A non parametric test similar to analysis of variance used to determine the significance of the differences among groups ranked data. Friedman's test - Answers A non parametric test similar to repeated measures analysis of variance used to determine the significance of the differences among groups of ranked data collected as repeated measures. Tolerance Pg. 143 - Answers The denominator of the VIF equation is referred to as tolerance, so that VIF is the reciprocal of tolerance. Assumptions of t-test Pg. 153 - Answers Assumptions of the t test; The population from which the samples are drawn is normally distributed. The sample or samples are randomly selected from the population. When two samples are drawn, the samples have approximately equal variance. the variance of one group should not be more than twice as large as the variance of the other. this is called homogeneity of variance. must be parametric. Independent t-test Pg. 156