PSYC204- Lecture#1

PSYC204- Lecture#1

1. Population vs. Sample

   • Population
     • all instances on some quantitative dimension
   • Sample
     • a subset of all instances on some quantitative dimension

2. Descriptive Statistics vs. Inferential Statistics

   • Descriptive Statistics
     • Parameter vs. Estimate
       • Parameter
         • symbols
           • Roman Numerals
             • mu
               • mean
             • sigma
               • standard deviation
         • Population
         • Txb Def: a number that is used to determine a population characteristic
       • Estimate
         • symbols
           • English Capital Letters
         • Sample?
   • Inferential Statistics
     • drawing a conclusion about the population based on the sample
     • Txb Def Statisitc
       • estimates the corresponding population parameter

3. Variables

   • Constants
     • C=5
   • Types of Variables
     • Qualitative
       • nominal
         • no order to them
           • ex: listing political parties
       • ordinal
         • there is order to them
           • ex: a scale measuring the satisfaction of students in a class
           • a, b, c
             • but you can't measure them
               • ex: you can't measure the distance between highly satisfied and not satisfied
                 • a-b =/= b-c
     • Quantitative
       • interval
         • 0 is arbitrary
         • arithmetic on intervals
         • ex: degrees F, C
       • ratio
         • 0 is meaningful
         • arithmetic on values
         • ex: weight
       • converting from interval to ratio
   • capital letters
     • X, Y

4. Discrete vs. Continuous

   • Discrete
     • number of students you can count entering the classroom late
       • can't be half a student
   • Continuous
     • the height/ weight of a student
   • depends on nature of variable

5. Methods of Sampling

   • simple random sampling
     • hardest
     • successive samples are independent
     • random sampling = central to statistical inference
     • equiprobable
       • def:
   • systematic sampling
     • select every nth member of the population the list
     • is systematic sampling random? It depends on the list
       • ex: depends on how you contact people i.e. from a phone book
         • If the list is not inclusive of the entire population then the sytematic sampling is not random

6. Response vs. Explanatory

   • manipulation, independent
     • # of pills
   • measurement, dependent
     • change of blood pressure