Confidence Intervals Flashcards
1
Q
What usually happens to standard error when sample size is increased?
A
Decreases
2
Q
What is standard error a measure of?
A
The precision of the point estimate (usually the mean of the sample measurements)
3
Q
What does a confidence interval show us?
A
A range of values within which the true population mean is likely to lie.
4
Q
What cases must be considered when specifying confidence intervals?
A
- When the standard deviation is known/estimated on a sample with 200 or more observations.
- Where the standard deviation has been estimated from a sample with less than 200 observations.
5
Q
How can a confidence interval be interpreted?
A
If this study is repeated many times, 95% of the times this interval will include the true population mean
6
Q
What data is used for samples greater or less than 200 observations?
A
- Greater= normal distribution data table
- Less= t-table
