Easy Level 1 Flashcards
Interpreting a confidence interval
I am 95% confident that the interval from __ to __ captures the true __.
Bias
A sampling method is biased if it consistently produces estimates that are too small or large
Advantage of using stratified random sample over SRS
Guarantees each strata is represented
They produce better information (more precise) than an SRS
Describing an association in a scatterplot
Direction
Outliers
Form
Strength
Scope of inference generalizing to a larger population
We can generalize the results of a study to a larger population if we used a SRS from that population
Interpreting LSRL y-intercept
When the x variable is zero, the y variable is predicted to be ___
Interpreting stand dev
Measures spread by giving the typical distance from the mean
Chi squared tests df and expected counts
GOF
- df = # of categories - 1
- expected counts = sample size times hypothesis of each categorical proportion
Homogeneity or independence
- df = (# rows - 1)(# columns - 1)
- expected counts = row total-col total/ total total
Factors that affect power
Sample size
Significance level
Data collection
Effect size
Power
Probability of avoiding a type 2 error = probability of finding convincing evidence that Ha is true when it is
Interpreting expected value/ mean
If we were to repeat the chance process many times the average value of ___ would be about ____
Scope of inference
Cause and effect
If we randomly assign treatments to experimental units we can conclude cause and effect
Association is NOT causation
Compare distribution
Shape
Outliers
Center
Spread
Greater than
Less than
Standard error vs Margin error
Standard error is an estimate of how far the value of the statistic typically differs from the true value of the parameter
The margin of error estimates how far we expect the parameter to differ from the statistic
What affects margin of error
Decreases when
- Sample size increases
- confidence level decreases
