Chapter 2 Statistics
2.0.1 What is statistics?
It is methods for Collecting, Describing, Analyzing,and drawing conclusions from Data with Random Variation. The methods are used for : a. Designing it •Planning research studies •How to obtain the required data
Description •Summarizing data •Exploring patterns in the data •Extract/condense information •Graphical pictures of the data
Inference •“Infer” from sample to population •Generalize •Make predictions based on the data
2.1 Terminology
2.1.1 Population
– total set of all subjects of interest – the entire group of people, animals or things about which we want information Example – All Iowa State University students • Elementary Unit – any individual member of the population Example – any Iowa State University Student
2.1.2 Sample
– subset of the population from which the study actually collects information – used to draw conclusions about the whole population Example – The class of STAT587-3 – All graduate ISU students – All male ISU students – 40 Randomly selected ISU students
2.1.3 Variable
– a characteristic of a unit that can vary among subjects in the population/sample Examples: – gender, nationality, age, income, hair color, height, disease status, grade in STAT 587-3, state of residence • Random Variable – Variable with random variation Example: – gender of the first person that will call you tomorrow – Your grade in the Final exam of STAT 587-3
2.1.4 Parameter
– numerical characteristic of the population – based on the whole population • Example – Proportion of male among ISU students • Statistic – numerical characteristic of the sample – calculated using the sample • Example – Proportion of male students in STAT 587-3
All chapter sections start with a second-level (##) or higher heading followed by your section title, like the sections above and below here. You can have as many as you want within a chapter.