A study measures a patient's serum cholesterol before and after a new lipid-lowering therapy has been given. What type of significance test should be used to analyze the data?

Ans. a (Paired t-test)SIGNIFICANCE TESTS: TYPESThe type of significance test used depends on whether the data is parametric (usually normally distributed) or non- parametric.Parametric Tests# Student's t-test - paired or unpaired# Pearson's - correlationNon-parametric Tests# Wilcoxon matched-pairs - compares the medians obtained# Mann-Whitney - unpaired data# Chi-squared test - used to compare proportions or percentages# Spearman, Kendall rank - correlationTypes of Scales in StatisticsType of scaleDescriptionKey wordsExamplesNominal (categorical)Different groups"This" as opposed to "that"Gender, comparing among treatment interventionsOrdinalGroups in sequenceComparitive quality, rankOlympic medals, class rank in medical schoolIntervalExact differences among groupsQuality, mean and standard deviationHeight, weight, blood groups drug dosageRatioInterval + true zero pointZero means zeroTemperature measured in degrees KelvinTypes of Scales and Basic Statistical TestsVariableName of statistics testIntervalNominalCommentPearson20Is there a linear relationship?Chi-square02Any number of groupst-test11Two groups onlyOne-way ANOVA11Two or more groupsMatched pairs t-test11Two groups, linked data pairs, before and afterRepeated measures ANOVA11More than two groups, linked dataPaired data refers to data obtained from a single group of patients, e.g., measurement before and after an intervention. Unpaired data comes from two different groups of patients, e.g., comparing response to different interventions in two groups.