“There are three kinds of lies: lies, damned lies, and statistics” Benjamin Disraeli

What is STATISTICS? A collection of methods for: Planning Experiments Obtaining… Organizing… Summarizing… Presenting… Analyzing… Interpreting… and Drawing Conclusions from… DATA

We apply statistics to 2 groups Populations Samples The entire group of items or individuals being considered. Examples: scores, people, measurements A small group of items or individuals chosen to represent the total population. Example: this class is a sample from the entire population of this school

The Nature of Data Quantitative vs. Qualitative ??? Quantitative Data “numbers” Qualitative Data “categories” Discrete : number of possible values are countable using integers, i.e. 0, 1, 2, 3,… OR Continuous: infinitely many possibilities, with no gaps, a continuum Temperature Number of Children per Family Students in the classroom Height Quantitative data can be either…

Classifying Data 4 Levels of Measurement Nominal OrdinalRatio Interval Names, labels, or categories only Data cannot be ranked at all EX: Religious Preference Preference, Gender Similar to Ordinal, but we can find meaningful differences between data No “zero” or starting point Some ranking, but differences are meaningless. Same as Interval, but Ratio has a true zero or starting point. EX: Temp. (F & C), People’s Height Good/Bad, Letter GradesEX: Lengths, Distance traveled, T(K)

PRACTICE mg of tar in cigarettes number of people in a car high to low temperature in any day weight time number of children in the average family Avg / above avg / below avg Nicotine contents of cig.’s Today’s temp. in Celsius Colors of M&M candies Grades (A, B, C, D, F) Exam scores Discrete or Continuous ?Nominal / ordinal / interval / ratio ?

PRACTICE mg of tar in cigarettes number of people in a car high to low temperature in any day weight time number of children in the average family Avg / above avg / below avg Nicotine contents of cig.’s Today’s temp. in Celsius Colors of M&M candies Grades (A, B, C, D, F) Exam scores Discrete or Continuous ? Continuous Discrete Continuous Discrete Nominal / ordinal / interval / ratio ? Ordinal Ratio Interval Nominal Ordinal Ratio

Uses of Statistics EEEEEEnormous…statistics are everywhere Political Surveys and opinion polls Manufacturing controls Medical and medication controls fatality rates which influence insurance, legislation, medical practices Biology and natural sciences, endangered species, wildlife control Sports …and much much more