Populations and Samples MARE 250 Dr. Jason Turner

Key Concept of the Day… Defining Populations Sampling populations for statistical testing

Sampling Populations The primary objective of statistic analysis is to infer characteristics of a group of data by analyzing the characteristics of a smaller sampling group Populations –

Samples from Populations Populations of interest are often so large as to render the obtaining of all measurements unfeasible Samples – To reach valid conclusions about populations by induction from samples, statistical procedures typically assume that the samples are obtained in a random fashion Random Sampling –

Samples from Populations

Average from Sample: Average from Population: Maximum Sustainable Yield (MSY)

Samples from Populations

Average from Sample: Average from Population:

Parameters and Statistics Measure of Central Tendency – Measure of Dispersion – Parameter – Statistic – Population parameters – Greek letters; Σ Χ μ γ Sample statistics – Latin letters; s, x, y

Good Statistics, Bad Statistics

3 Rules for Good Statistics

Samples from Populations Average from Sample1: Average from Sample2: Average from Sample3: Average of all Samples: Average from Population: