Section 1.1 Introduction to the Practice of Statistics

statistics

science of data

data

information

prices and costs, numbers of items sold, employee names, product names.

the process of statistics

Design the study, Collect the data, Describe the data, Make inference, Take action

Population vs. Sample

entire group vs. specific group

Individual

collected data that can be associated with a single element in a sample

Descriptive statistics

organizing, collecting, computing, displaying, analyzing

Inferential statistics

drawing conclusions

Parameter

number describing a whole population

(the average length of a butterfly. This is a parameter because it is states something about the entire population of butterflies)

statistic

number describing a sample

(the average number of points earned by students in that one math class at the end of the term)

the steps in the Process of Statistics

• Step 1: Write your hypotheses and plan your research design.

• Step 2: Collect data from a sample.

• Step 3: Summarize your data with descriptive statistics.

• Step 4: Test hypotheses or make estimates with inferential statistics.

• Step 5: Interpret your results

the research objective. 

an idea you want to understand deeper by performing research

Discrete

countable (whole numbers)

continuous

measurable

temperature, weather, energy, speed

nominal

qualitative only, labels (sorting info, ex, diff hair color)

Ordinal

quantitive or qualitative, order (rank items)

internal

quantitive only, sum/differences. zero is a position, negative allowed (temperature like -35)

ratio

quantitative only, zero cannot be separated