Ahmed Alsanousi CSC 464 Existing instruments Oscilloscope Re-use rating scale Create an instrument Survey Checklist Paper and pencil Tangible and intangible Measurement is limiting the data of any phenomenon –substantial or insubstantial– so that those data may be interpreted and, ultimate, compared to a particular qualitative or quantitative standard. Nominal Scales Ordinal Scales Interval Scales Ratio Scales Comes from Latin “nomen” means Name Used to Limits the data Example: Boys & girls in class Statistical procedures could be used Mode: for most frequent occurrence Percentage: part of total Chi-square test: compare occurrence between categories > (greater than) < (less than) Used to rank-order our data Example: Classification by education degree Statistical procedures could be used Median: determine half-way Percentile rank: determine position of item in a group Two features 1. 2. Has equal units of measurements Zero point is arbitrarily Example: Temperature Statistical procedures could be used Mean Standard deviation Two features 1. 2. Has equal units of measurements Zero point is an absolute zero Example: Ruler Rarely used outside physical science Can express values in multiples or fractions If you can say that One object is different from another you have a nominal scale One object is bigger or better or more of anything than another You have a ordinal scale One object is so many units more than another You have a interval scale One object is so many times as big or bright or tall or heavy as another You have a ratio scale Reliability is the consistency with which a measuring instrument yields a certain, consistent result when the entity being measured hasn’t changes Example: waistline tape measure Interrater reliability Two testers, same result Test-retest reliability Retest in different occasions, same result Equivalent forms reliability Different versions or instrument, same result Internal consistency reliability Different items within instrument, same result 1. Getting two measures by using one form of reliability 2. Calculate how similar are the results