Basic Statistics With a touch of Probability

Making Decisions We make decisions based on the information we have. Statistics help us examine the information so we can make educated decisions vs. “guessing” or gut feelings. We make decisions based on the information we have. Statistics help us examine the information so we can make educated decisions vs. “guessing” or gut feelings.

Should I climb Mt Everest?

Not Me!

What is Statistics? Statistics is the study of how to collect, organize, analyze, and interpret numerical information from data. Statistics is the study of how to collect, organize, analyze, and interpret numerical information from data.

Vocabulary for Statistics Population – The entire group of interest. Population – The entire group of interest. Individual – people or objects in the population. Individual – people or objects in the population. Sample - a part of the population. Sample - a part of the population.

Variable Characteristic of the individual to be measured or observed.

Two Kinds of Variables Quantitative – has value or numerical measurement for which operations such as addition or averaging make sense. Exp. Average height of BKB players Quantitative – has value or numerical measurement for which operations such as addition or averaging make sense. Exp. Average height of BKB players Qualitative – describes an individual by placing the individual into a category or group (categorical) Exp. Male or female Qualitative – describes an individual by placing the individual into a category or group (categorical) Exp. Male or female

4 levels of measurement 1. Nominal – name only. Can not compare among data. (JW, ACCHS, Sab) names of league schools 1. Nominal – name only. Can not compare among data. (JW, ACCHS, Sab) names of league schools 2. Ordinal – some order of variables but no data values. Exp. Good, fair, poor 2. Ordinal – some order of variables but no data values. Exp. Good, fair, poor 3. Interval – like ordinal, but have values with no clear start or zero. Exp temp of students 3. Interval – like ordinal, but have values with no clear start or zero. Exp temp of students 4. Ratio – like interval but has start or zero. Can calculate a ratio. 4. Ratio – like interval but has start or zero. Can calculate a ratio.

Two Types of Statistics Descriptive Statistics – Organize, picturing, and summarizing information from samples or populations. Descriptive Statistics – Organize, picturing, and summarizing information from samples or populations. Inferential Statistics – method of using information from a sample to draw conclusions regarding a population. Inferential Statistics – method of using information from a sample to draw conclusions regarding a population.