Lecture 2 Flashcards
What’s a population?
The entire group of individuals or subjects about which the research wants information
what’s a Parameter
Specific characteristics of the population that the researcher wants to determine and make statements about
Typically denoted by Greek letters
What’s µ (mu)
The mean of the population
What’s η (eta)
the median of the population
What’s σ (sigma)
The standard deviation of the population
What’s σ^2 (sigma squared)
Variance of the population
What’s π (pi)
Proportion of successes in the population
What’s ρ (rho)
The correlation between two variables in a population
What’s a hypothesis
A statement about a population parameter
a conjecture or guess as to what one thinks the parameter value would be
Why do we need a sample?
The population is such that every subject or individual cannot be contacted or measured, & hence the value of the parameter can’t be determined
thus we select a subset of the population, determine the appropriate data for this subset of individuals, and then use this data to make statements about the population of interest
Sample
A subset of the population that we examine in order to gather the data required to make statements about the population and parameter of interest
Goal is to have the sample be representative of the population, meaning the characteristics of the population that are important are mimicked in the sample
What’s a statistic?
A descriptive measure computed or determined from data in a sample
Generally match identified parameters of interest - can be computed b/c we have sample data statistics
What’s n?
n represents the number of subjects in the sample size
What’s x-bar
x-bar represents the mean of the sample
What’s M
median of the sample
