Basic Statistical Methods

analysis of variance average binomial biserial centile point chance Chapter computed correct correlation coefficient Correlation ratio data in Table degrees of freedom discrimination distractors divided equal equation error of estimate error of measurement expected frequencies Figure frequency distribution frequency polygon grades graph intelligence test scores item analysis item correctly item difficulty low groups Mann-Whitney mean square median median test method midpoint multiply N₁ N₂ normal curve normally distributed null hypothesis obtained pairs Pearson percent level percentages phi coefficient plot point-biserial population mean predicting probability problem proportion raw score regression relationship reliability coefficient sampling distribution scattergram scatterplot sets of data shown in Table smaller square root standard deviation standard error standard score statistics subtract sum of squares Suppose t-test tally technique true score U₁ uncorrelated data validity coefficient values in column variables Wald-Wolfowitz runs test X-axis Y-axis z-score Σχε