STA 2023 Chapter 8

degrees of freedom

# of observations that can be chosen freely df= n-1

t distribution

a continuous distribution with a specific type of bell shape curve mean = 0 standard deviation = square root df/(df-2) Compared to z distribution: wider & flatter larger standard deviation

interval estimate

constructed around point estimate, likely to contain the corresponding population parameter lower limit - upper limit each interval estimate has a confidence level

inferential statistics

helps make decisions about some characteristics of a population based on sample size

confidence interval

interval constructed around the sample statistic, based on confidence level to estimate the population

Margin of Error (E)

the number added or subtracted to the value of the sample statistic/ point estimate used to create a confidence interval

confidence level

used to make a probabilistic statement how much confidence we have that this interval contains the true population parameter (1-alpha)100% i.e. 90%, 95%, 99%

estimate

value of a sample statistic that is used to find the population parameter

point estimate

value of the sample statistic used to estimate the population parameter represented by p-hat

estimation

procedure where a numerical value is assigned to a population parameter based on information collected from a sample

estimator

sample statistic used to estimate population parameters