Bailey N-
What is a point estimate?
A single number used to approximate a pop. parameter (comes from the sample)
-
What is an interval estimate?
A range of numbers between which a pop. parameter is likely to fall
-
Why is an interval estimate preferable over a point estimate?
Because they provide a measure of uncertainty within our result by using a range
-
What is a confidence interval?
A range of values within which the pop. parameter is estimated to fall and is defined by our confidence level
-
What is a confidence level in relation to a confidence interval?
The confidence level is the likelihood (as a %) that a specific interval will contain the pop. parameter, and the width of said interval is determined by the confidence level
-
What are 2 factors that effect the width of a confidence interval?
1. Sample size (larger samples result in smaller errors) = makes the interval narrower and more precise
2. Confidence level = A higher confidence level makes the interval wider and less precise
-
If you surveyed a sample of 144 students about the # of drinks they had on Saturday night and the mean = 9 and S.D = 3, interpret a 99% confidence interval for the mean # of drinks on a Saturday night for the entire school population
We're 99% confident that the mean # of drinks that the average student drinks on a Saturday night is between 8.4 - 9.6 drinks
-
If you surveyed 1,000 Gotham city residents and 56% of them said they support Batman's vigilantism, interpret a 95% confidence interval for what % of all Gotham city residents support him
We're 95% confident that the true number of Gotham city residents who support batman is between 52% - 59%
