1. Statistics Definition of Statistics Statistics – Numerical Data
Statistics – A Body of Theory and Methods Applied to Data to Aid in Decision-Making

2. Areas of Statistics Descriptive Statistics Probability
Inferential Statistics

3. Summation Notation Observations: X1 X2 X3 X4 …. Xn
Sum of Observations: ∑Xi = X1 + X2 + X3 + X4 …. + Xn
Sum of Squared Observations: ∑Xi2 = X12 + X22 + X32 + X42 …. + Xn2
Rules for Summations:
( c – Constant)
∑c = n•c Special Case: ∑1 = n
2) ∑c•Xi = c•∑Xi
3) ∑(Xi + Yi) = ∑Xi + ∑Yi

4. Population vs Sample
Population – A collection of all observations of a characteristic of interest
Sample – A portion of a population
Parameter – a measure of a population (µ,σ)
Statistic – a measure of a sample (X,s)

5. Data Types Nominal Data – Descriptive Titles with no natural order.
Ordinal Data – Data with a natural order but no distance measure
Interval Data – Data with distance measure but no true zero
Ratio Data – Data with a true zero.

6. Example Employee Ms Abba . . . . . . . . . . . . Mr Zee Sex F M
Marital S M
Age
Salary , ,000
Job Manager Foreman
Tenure

7. Two Major Data Classifications
Qualitative Data – Non-Metric
Nominal
Ordinal
Quantitative Data – Metric
Interval
Ratio