AP Statistics Chapter 7

STUDY
PLAY
parameter (think "parameter" begins with a p)
a number that describes some characteristic of the population (typically mu or p)
statistic (think "samle" begins with a s)
a number that describes some characteristic of a sample (typically x bar or p hat)
sampling distribution of a statistic
the distribution of values taken by the statistic in all possible samples of the same size from the same population
biased
not estimating the true center well
unbiased
the mean of its sampling distribution is equal to the true value of the parameter being estimated
the smaller the variability
the larger the sample ...
variability of a statistic
is described by the spread of its sampling distribution
p-hat
a sample proportion (formula: x/n)
the formula for the mean of the sampling distribution of p-hat
the formula for the standard deviation of the sampling distribution of p-hat
the formula for the standard deviation of the sampling distribution of x-bar
the formula for the mean of the sampling distribution of x-bar
µ "sub" x = µ
Central Limit Theorem (CLT)
Draw an SRS of size n from any population with mean (µ) and finite standard deviation (σ). This says that when n is large (n ≥ 30) the sampling distribution of the sample means (x-bar) is approximately Normal.