Introduction to the Practice of Statistics

Vocabulary

• Statistics - the science of collecting, organizing, summarizing and analyzing information to

draw conclusions

• Data - a fact or proposition used to draw a conclusion or make a decision; list of observed

values for a variable

o Data describes characteristics and can be quantitative or qualitative

• Population - the entire group to be studied

• Sample - a subset of the population being studied

• Individual - a person or object that is a member of population being studied

• Statistic - a numerical summary of a sample

• Parameter - a numerical summary of a population

• Descriptive Statistics - describes data through numerical summaries, tables, and graphs

• Inferential Statistics - take results from a sample, extend it to the population and measure

the reliability of the result

• Qualitative Variable - or categorical, variables allow for classification of individuals based

on some attribute or characteristic (Gender, Zip Code) the corresponding data that is

collected is called Qualitative Data

• Quantitative Variable - provide numerical measures of individuals (Temperature, days a

student studies) the corresponding data that is collected is called Quantitative Data

o The values of quantitative variables can be added or subtracted and provide

meaningful results

• Discrete Variable - quantitative variable that has either a finite number of possible values

or a countable number of possible values

• Continuous Variable - quantitative variable that has an infinite number of possible values

that are not countable

The Process of Statistics

Step 1: Identify the Research Objective

o The researchers need to determine detailed questions to be answered

Step 2: Collect the Data Needed to Answer the Question(s)

o Data collection is typically done on a sample of a population and choosing the

sample correctly is very important

Step 3: Describe the Data

o Descriptive statistics allow the researcher to obtain an overview of the data

collected

Step 4: Perform Inference

o Using different statistical techniques allow the results from the sample to be applied

to an entire population reliably

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