POPULATION
a collection of persons, things, or objects under study.
SAMPLE
a portion (or subset) of the larger population, to study & gain info about the population. Data are the result of sampling from a population.
STATISTICS
a number that represents a property of the sample. An estimate of a population parameter. (the
PARAMETER
a number that is a property of the population (average - mean of something involving the whole group)
REPRESENTATIVE SAMPLE
The sample must contain the characteristics of the population in order to be a representative sample.
VARIABLE
notated by capital letters such as X and Y, is a characteristic of interest for each person or thing in a population.
VARIABLE 1
Variables may be numerical (quantitative) or categorical (qualitative)
QUALITATIVE VARIABLE (categorical)
place the person or thing into a category
QUANTITATIVE VARIABLE (numerical)
take on values with equal units such as weight in pounds and time in hours
DESCRIPTIVE STATISTICS
organizing and summarizing data
INFERENTIAL STATISTICS
Statistical inference uses probability to determine how confident we can be that our conclusions are correct.
QUALITATIVE DATA
is the result of categorizing or describing attributes of a population. Qualitative data are generally described by worlds or letters.
QUANTITATIVE DATA
are always numbers. Quantitative data are the result of counting or measuring. (Ex money, weight, pulse rate (etcetera) Quantitative data may be either discrete or continuous.
QUANTITATIVE DISCRETE DATA
all data that are the result of counting
QUANTITATIVE CONTINUOUS DATA
All data that are the result of measuring
NOTE ON QUANTITATIVE DATA
example: number of books in the backpacks are discrete data and the weights of the backpacks are continuous data