CH.1 - Basis

Questions: What is data? How do we use data?

What is data?

Info

When collecting info ___

distinguishing the info gathered is important

Subjects are ___

individuals use to collect info

What are variables?

features measured about the subjects

Quantitative data

Numerical data

Categorical data

sorting and organizing data into different categories or classifications

List the 3 main components of the Statistical Method

1. Design = how data is obtained

2. Description = summarizing the data obtained; identifies patterns

3. Inference = making decisions or predictions

What is population?

All individuals in the study

What is a Census?

gathering data on each individual in a population

What is a sample?

subset of the population that we gather data on and use to make inferences about a population

A sample taken well will have ___

similar consistency to the population

Parameter

numerical value summary of the population data; a feature of the population

Statistic

numerical value summary of the sample data; serves as estimates for population parameters

What is variation?

Repeating the same process that may different results each time

What is sample variability?

variation between samples

With sampling variability, what happens to the statistic?

It should be expected to change between samples

Is the parameter a fixed value? What happens to the parameter when sampling a population?

Yes the parameter is a fixed value

Sampling the population has no effect on its parameter

μ

population mean (parameter) or mu (quantitative variable)

x̄

sample mean (statistic) or x-bar (quantitative variable)

p

population proportion (parameter) or p

p̂

sample proportion (statistic) or p-hat

What is the equation for p̂?

# in category of interest / total # sampled

Proportions is another way to express a ___

percentage or fraction

Describing cateorgiol variables using

proportions

Describing quantitative variables using

means