AP Stats Unit 8 Vocab

Point estimator

Statistic that provides an estimate of a population parameter

Point estimate

Specific value of a point estimator from a sample

Confidence interval

Gives an interval of plausible values for a parameter. The interval is calculated from the data and has the form: point estimate plus or minus margin of error

Margin of error

The difference between the point estimate and the true parameter value will be less than the margin of error in the C% of all samples, where C is the confidence level.

Confidence level

Success rate of the method for calculating the confidence interval. In C % of all possible samples, the method would yield an interval that captures the true parameter value.

Standard error

When the standard deviation of a statistic is estimated from data, the result is standard error of the statistic.

One sample z - interval for a population proportion

When the random, 10 %, and large accounts conditions are met, A C % confidence in the interval for the proportion P is

T distribution

Draw an SRS of size n from a large population that has a normal distribution with mean and standard deviation

Degrees of freedom

The number of independent values or quantities that can be assigned to a statistical distribution

Standard error of the sample mean

Sx/√n where sx is the sample standard deviation

One sample T interval for a population mean

When the random, 10%, and the normal / large sample conditions are met, A C % confidence interval for mean is X bar +/- t sx/√n.