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Chapter #1

james leach English

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Chapter #1

Statistics
- the science of conducting studies to collect, rganize, summerize, analyze and draw conclusions from data
- Variable
  - characteristic or attribute that can assume different values
- Data
  - value that a variable can assume
  - Qualitative: Categorical
  - Quantitative: Numerical, Can be ranked
    - Discrete Countable Ex: 5, 29, 8000, etc.
    - Continuous: Can be Decimals Ex: 2.59. 312.1 ect.
- Population
  - consists of all subjects that are studied
- Sample
  - subset of the population
- Descriptive statistics
  - consists of the collection, organization, summarization and presentation of data
- Inferential statistics
  - consists of generalizing from samples of popuations, performing estimations and hypothesis tests determining relationships among variables, and making predictions
Levels of Measurement
- Nominal
  - Categorical (names)
- Ordinal
  - Nominal. plus can be ranked (order)
- Interval
  - ordinal. plus intervals are consistent
- ratio
  - interval, plus ratios are consistent, true zero
Samples of Techniques
- Random
  - random number generator
- systematic
  - Every K^th subject
- stratified
  - divide population into layers
- Cluster
  - Use intact groups
- Convenient
  - Mall surveys
- Sampling Error
  - Sample Vs. Population
Experimental Design
- Observational Study
  - Observes and tries to draw conclusions based on the observation
- Confounding Variable
  - influences the dependent variable but cannot be separated from the independant variable