advertisement

AP Statistics Section 11.4 B A significance test makes a Type I error when it rejects H 0 and the H 0 is really true. ___________________________________ P(Type 1 error ) = ___ A significance test makes a Type II error when __________________________________. it fails to rejects H 0 and the H a is really true fail to reject H 0 Type II errors are always computed at a particular value for H a . Calculating the probability of a Type II error by hand is possible but unpleasant. It’s better to let technology do the work for you. You will not be expected to find P(Type II error) on the AP exam. If the probability of a Type II error for a particular Ha is high, this means that the test is not sensitive (or tuned-in) enough to regularly detect that Ha. power more sensitive 1- Probability of not rejecting H 0 when H a is true Calculations of p-values and calculations of power both tell us what would happen if the test were repeated many times. A p-value tells us what would happen supposing that the ___________, H 0 is true while power describes what would happen supposing a particular __________. H a is true When planning a study that will include a significance test, a careful user of statistics decides what alternative values of the parameter the test should detect and checks that the power is adequate. The power depends on which particular parameter value in H a we are interested in. To calculate power, we must fix an so that there is a fixed rule for rejecting H 0 . Increasing the Power High power is always desirable. Along with ____ 95% confidence intervals and ____ 5% significance tests, ____ 80% power is becoming a standard. The best advice for maximizing the power of a test is to choose as high an ___level as you are willing to risk AND as large a sample size as you can afford. increase the probability of a Type I error