Chapter 5: Foundations For Inference Flashcards
(20 cards)
What is a point estimate?
A sample statistic used to estimate a population parameter.
What is sampling error?
The difference between a point estimate and the true population parameter.
What does bias refer to in sampling?
A systematic tendency to over- or under-estimate the true parameter.
What is the Central Limit Theorem (CLT)?
It states that the sampling distribution of the sample proportion is approximately normal.
What is the standard error formula for a proportion?
SE = sqrt[p(1 - p) / n]
When can the CLT be applied?
When sampled observations are independent and there are at least 10 expected successes and failures.
What is a confidence interval?
A range of plausible values for the population parameter.
What is the formula for a 95% confidence interval?
Point estimate ± 1.96 × SE
How does increasing the confidence level affect the interval?
It makes the interval wider.
What does a 95% confidence level mean?
If we repeated the sampling process many times, about 95% of the intervals would contain the true parameter.
What is a hypothesis test?
A method for testing a claim about a population parameter.
What is the null hypothesis (H0)?
The default assumption, typically that there is no effect.
What is the alternative hypothesis (HA)?
The claim we are testing for, indicating a difference or effect.
What is a p-value?
The probability of observing data as extreme or more if the null hypothesis is true.
When do we reject the null hypothesis?
When the p-value is less than the significance level (typically 0.05).
What is a Type I Error?
Rejecting the null hypothesis when it is actually true.
What is a Type II Error?
Failing to reject the null hypothesis when it is actually false.
What is a one-sided test?
A hypothesis test where the alternative hypothesis is directional.
What is a two-sided test?
A hypothesis test where the alternative considers deviations in both directions.
What does increasing the sample size do to the standard error?
It decreases the standard error.
