Statistics III Flashcards
(7 cards)
When is σ underscore x-bar = σ / square root n used?
It is used when you know the population standard deviation. It tells how varied the sample mean is. It is used in a-tests for the population mean.
When do you use σ subscript p-hat = square root p(1-p) / n?
When you know the true population proportion. It measures how much sample proportions will vary. It is used in a-tests when the population proportion when p is known.
When is SE subscript x-bar = s / square root n used?
When the population standard deviation is unknown. It estimate how much the sample mean varies. It is used in confidence intervals.
When is SE subscript p-hat = square root p-hat (1 - p-hat) / n used?
It is used when you do not know the true population proportion. It is used for z-tests and confidence intervals for proportions.
When is MOE = +2(standard deviation) used?
It gives the 95% confidence intervals.
When using the margin of error formula, what can you replace σ subscript x-bar with?
σ / square root n
What is a synonym for standard deviation?
Standard error
