Statistics

Statistics

1. Science of collecting , organizing, analyzing and interpreting data

   • Descriptive
     • Branch of statistics that involves the organization, summarization, and a display of data
   • Inferential
     • Branch that involves using a sample to draw conclusions about a population

2. Data

   • Information coming from observation, counts, measurements or responses (value a variable can assume)
     • Collection of data values=Data Set Each of the data set is called data value or datum
       • Types of data sets
         • Population
           • All subjects that are being studied
             • A numerical description of it it is called a parameter
         • Sample
           • Is a subset of a population
             • A numerical description of it it is called a statistic
           • (Sample data must be collected using an appropriate method, if not the data are of not value
   • Types of Data
     • Qualitative
       • Consists of attributes, labels, or non numerical entries
     • Quantitative
       • Consist of numerical measurements or counts

3. Variables

   • Characteristics or attributes that can assume different values
     • Types of Data & Variables are the same
       • Quantitave
         • Discrete Variables
           • Assume values that can be counted
         • Continuous variables
           • Assume an infinite number of values between any two specific valves (Often use fractions and decimals)
       • Qualitative
     • (Variable whose valves are determined by chance are called Random Variables

4. Data and variables & interrelated

5. Levels of Measurement

   • Nominal
     • Qualitative only (No math here)
   • Ratio
     • Similar to interval (Zero is an inherent zero) A ratio of data is formed so that one data is expressed as multiple of another
   • Ordinal
     • Qualitative or Quantitative Can be arranged in order or ranked
   • Interval
     • Can be order and can calculate meaningful differences (Zero represents a position on a scale)