Statistic

Statistic

1. POPULATION: a total observation that can be made .

2. Sample: a small part or quantity intended to show what the whole is like .

3. Estimation: e.g, estimate the population mean weight using the sample mean weight .

   • Hypothesis testing: e.g., test the claim that the population mean weight is 70 kg.
     • With replacement: a member of the population may be chosen more than once(picking the candy from the bowl). without replacement: a member of the population may be chosen only once (lottery ticket)
       • random:population does not has the same choices of being selected .
         • Simple random sample: is a subset of individuals (a sample) chosen from a larger set (a population).
         • stratified sample: refers to a type of sampling method . With stratified sampling, the researcher divides the population into separate groups, called strata. Then, a probability sample (often a simple random sample ) is drawn from each group.
         • cluster sample: is a sampling plan used when mutually homogeneous yet internally heterogeneous groupings are evident in a statistical population. It is often used in marketing research. In this sampling plan, the total population is divided into these groups (known as clusters) and a simple random sample of the groups is selected.

4. variable describes a person , place, thing,or idea. varies across people and objects.