Sample vs. Population

http://www.discover6sigma.org/post/2005/12/statistics-simplified/

Descriptive Statistics used to create numerical summary of sample data.

Inferential Statistics used to extend sample data to the population with a certain reliability.

Bias?

Descriptive Statistics

• Describes results of sample data without making any general conclusions about the population
• Organizes and summarizes data through numerical summaries, tables and graphs
• Describe the shape, spread, and central tendency of the data

Inferential Statistics

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Allow you to make predictions or generalizations about a population

Shape

http://www.pearsonhighered.com/sullivan/sul_alg_trig/Ch2_org_summ_data_.pdf

Spread

https://controls.engin.umich.edu/wiki/index.php?title=Comparisons_of_two_means&oldid=30807

Central Tendency

https://controls.engin.umich.edu/wiki/index.php?title=Comparisons_of_two_means&oldid=30807

What is the null hypothesis here?

https://twitter.com/datarobot/status/656456846463643648

P-values equal to or less than 0.05 will indicate that the null hypothesis can be rejected.

Regression�

Null hypothesis: There is no relationship between x and y

Test by comparing the slope of line to 0 (slope of 0 = no relationship) using a t-test in Vassarstats

Is there a relationship between leaf length and width?