All Flashcards
Define confidence interval.
A range of values likely to contain the true population parameter.
What is a point estimate?
The single best estimate of a population parameter, like the sample slope.
Define margin of error.
The 'buffer zone' around the point estimate, calculated using the t-score and standard error.
What are residuals?
The differences between observed y-values and y-values predicted by the regression line.
Define standard deviation of residuals.
Measures the spread of data points around the regression line; also known as the standard error of the estimate.
What are the differences between the t-distribution and the normal distribution?
T-distribution: Used when population standard deviation is unknown, heavier tails | Normal distribution: Used when population standard deviation is known, lighter tails.
What are the differences between a point estimate and a confidence interval?
Point estimate: Single value estimate of a parameter | Confidence interval: Range of plausible values for a parameter.
What are the differences between the standard deviation and the standard error of the slope?
Standard deviation: Measures the spread of data around the mean | Standard error of the slope: Measures the variability of the sample slope.
What are the differences between a 90% confidence interval and a 99% confidence interval?
90% CI: Narrower, less confidence | 99% CI: Wider, more confidence.
What are the differences between interpreting a confidence interval and interpreting a confidence level?
Confidence Interval: Provides a range for the true parameter. | Confidence Level: Indicates the success rate of the method if repeated many times.
What is the formula for the standard error of the slope?
, where s is the standard deviation of the residuals.
How do you calculate the margin of error for a confidence interval for the slope?
Margin of Error = t-score * Standard Error of the slope.
What is the general structure of a confidence interval?
Point Estimate ± Margin of Error
What is the formula to calculate degrees of freedom in linear regression?
df = n - 2, where n is the sample size.
How do you calculate the confidence interval for the slope of a regression line?
Sample Slope ± (t-critical value * Standard Error of the slope)