Presentation on theme: "Info 2040 Foundation of Quantitative Analysis"— Presentation transcript:
1 Info 2040 Foundation of Quantitative Analysis Week 2-1
2 Class ActivitiesThink of a question that lead you to collecting a data set (comprising of data and cases)Eg. What types of telecommunication operators do students in info 2040 subscribed to? Or what are the weights of the students in this class?Create a data set (a minimum of 50 cases) in the Excel spreadsheetArrange them as data and casesYou may find your data in the internet – describe what the data is about, or for what purpose
3 Measurement The form in which our data represented What do we normally measure?How do we measureWhat kind of measurements can you find out there?Why do we measure?Most of the time we measure variablesWhat is a variable?
4 Measurement and Variable Measurement – the use of any rule to assign numbers to cases so as to represent the presence or absence or quantity of some attribute possessed by each caseVariable – an attribute or characteristic that varies from one case to the next
5 Rules in Measuring Very important Depend on what is being measured More than one way to measure an attributeSometimes called “scale” or “level” or measurementWill determine how we choose the statistical tools
7 Nominal Scale The lowest level of measurement Describes in terms of quality of each case – “what kind” NOT “how much”Eg. Gender – male or female,Describe presence or absence of an attribute – eg. Yes or NOWhen assigned numbers, the difference has no mathematical valueHow do we use statistics to describe data in this category?
8 Ordinal Scale Involves assigning numbers to cases Conveys quantitative information about casesEg. Strongly agree = 1, Agree = 2, Somewhat agree = 3, Disagree = 4, Strongly disagree = 51 is < 2, 3 is > 22 – 1 ≠ 3 -2 (the different has no mathematical value)
9 Interval ScaleScores on the scale variable determined by the number of fixed-sized unitsNo absolute 0 in the variable attributeArbitrary 0 point – 0 does not means complete absence of attribute0 represents low quantityThe different can be mathematically manipulated – 2 -1 = 3 – 2 = 1What are other examples of variables measured using interval scale?
10 Ratio Scale Highest, most flexible level of measurement Data available themselves to all of most powerful statistical proceduresSimilar to interval scale EXCEPT0 means 0What are the example of variables measured using ratio scale?
11 Assignment 2 In continuation with the data set earlier, Complete the data sheet with at least 50 cases and at least 4 variables that are measured with nominal, ordinal, interval, and ratio scale.