lecture 1a

• There are four scales of measurement that are commonly

  used in statistical analysis: ▫ Nominal scale,

  ▫ Ordinal scale,

  ▫ Interval scale,

  ▫ Ratio scale.
• Nominal scale: Values assigned to variables represent a descriptive category, but

  have no inherent numerical value with respect to magnitude.
• In nominal scale numbers may be used to represent the variables but the numbers do not have numerical value or relationship.
• Gender is an example of a variable that is measured on a nominal

  scale. Individuals may be classified as "male" or "female", but

  neither value represents more or less "gender" than the other
• In ordinal scale each value has a unique meaning, and it has

  an ordered relationship to every other value on the scale.
• The ordinal scale allows for rank order (1st, 2nd, 3rd, etc.) by which

  data can be sorted, but still does not allow for relative degree of

  difference between them.
• The interval scale allows for the degree of difference between items,

  but not the ratio between them.
• With an interval scale, you know not only whether different values

  are bigger or smaller, you also know how much bigger or smaller

  they are.
• ratio scale is a scale of measurement of data according to which the differences between values can be quantified in absolute but not relative terms.
• A ratio scale possesses a meaningful (unique and non-arbitrary)

  zero value
• Examples of ratio scale include mass, length, duration, energy and many economic variables expressed in money
• two main forms of data coming from a statistical survey: Ordered arrays and Frequency distributions
• is this grouped or ungrouped frequency distribution?

  grouped

  
• is this grouped or ungrouped frequency distribution?

  ungrouped

  
• Histogram is a recital bars chart in which the

  rectangular bars are constructed at the

  boundaries of each class.
• The percentage polygon is formed by having the midpoint of each class represent the data in the class and then connecting the sequence of midpoints at their respective class percentages.
• Frequency curve is a modification of a frequency polygon with the sharp corners rounded
• Box-and-Whisker Plot isa way of looking at a data set in an effort to determine its central tendency, spread, skewness, and the existence of outliers.
• Pareto Diagram, named after Vilfredo Pareto, is a type of chart that contains both bars and a line graph, where individual values are represented in descending order by bars, and the cumulative total is represented by the line.
• what type of chart is this?

  steam and leaf display