Science of collecting, organizing, summarizing, and analyzing information to draw conclusion or answer questions.
Stages of statistics
- 1 Collect.
- 2 Analize.
- 3 Draw a conclusion or answer.
Types of statistics
- 1 Descriptive.
- 2 Inferential.
It consist of organizing and summarizing data using table graph or simple calculation
It uses methods that take a result from a sample extend of population and measure the reliability of the results.
Is the entire group.
is a subgroup of from the population.
Numerical value used to describe population.
Numerical value used for a sample.
Numbers can be counted
Ex: 45 students
Numbers can not be counted:
- Ex: - 355 ml coke can.
- - 10:00 am
Levels of measurement:
- 1 Nominal.
- 2 Ordinal.
- 3 Interval.
- 4 Ratio.
Measurements are names, labels, or categorical data.
- As addition: There is no ordering system.
- EX: Quiz, HW, Final. (order doesnt matter, once added, give same result)
- Names, labels, (similar as ordinal. Difference is: Names have no mathematical difference)
- EX: S (small), M (Medium), L (large).
Numbers. difference has a meaning
as addition: Zero is not a natural starting point.
EX: Temperature, elevation.
It measures the value of the response variable without attempting to influence the value of either the response or explanatory values. (Only observes, gathers data)
A research assigns the individuals in a study to a certain group, Intentionally changes the value of the explanatory value, and then records the value of response. (Do a lab, then records the change)
The process of using chance to select an individual from a population to ve included in a sample. (pick one by one)
Simple random sample:
(Always same chance, group)
A sample of size "n" from a population size "N" is obtained through simple random sample if every possible sample size "n" has an equal chance of being selected.
Other effective methods of sampling:
- 1 convenience sample.
- 2 Systematic.
- 3 Stratified.
- 4 Cluster.
Individuals are easily obtained.
Select every kth individuals from a population
Ex: HW 1.1- Do 1-100 every odd
Separate population into non-overlaping groups then obtain samples from each group.
Obtain samples by selecting all samples from a selected group.
Stratified VS Cluster
- 1.- Divide population into some groups
- 2.- Pick all groups l 2.- pick some groups
- 3.- Pick some samples l 3.- pick all samples