AP STATS Notes

Who We Are Studying

Population

  • Entire group of individuals

Sample

  • Subset of individuals in the population we wish to collect data

  • Subset of a population

  • Allows you to make an inference on the population if it is representative

  • Must be specific

Census

  • Collects data from every individual in the population

  • More precise

Sample Survey

  • Collects data from a sample that is chosen to represent a specific population

  • Gives estimates

 

Planning a Study

  • Observational Study: Planning data in the future

    • Retrospective: Using data from the past

    • Observational: Using data from the present and future

 

How to Random Number Generate

  1. Label each member of population a numerical number of equal length (001, 002, ect)

  2. Read consecutive groups of digits of the appropriate length from the table. Ignore digits not in your sample and duplicate data

  3. Choose the individuals that correspond to the selected integers

 

To generate a random sample of 10 plots, you must set the lower limit of your calculator at 0 and the upper limit at 100, since that is the number of circular plots. Then, you would set the n value as 10, since it’s the size of the wanted sample population

 

Replacement

  • Sampling without replacement

    • A individual can only be selected once

    • No repeats

  • Sampling with replacement

    • An individual can be selected more than once

    • Repeats are allowed