Estimation Procedures Flashcards
What is a point estimate?
A single sample statistic used to estimate a population parameter.
What is a confidence interval?
A range of values within which a population parameter is expected to fall.
What is the margin of error?
Half of the confidence interval’s width.
What is bias in estimation?
When the mean of the sampling distribution does not equal the population parameter.
What is efficiency in estimation?
When the sample estimates are closely clustered around the mean.
How does sample size affect efficiency?
Larger samples decrease standard error, making estimates more precise.
What is alpha (α) in hypothesis testing?
The probability of making an error (not including the population parameter in the interval).
What confidence level corresponds to α = 0.05?
95% confidence level.
What does a 95% confidence level mean?
If repeated samples were taken, 95% of the confidence intervals would contain the population mean.
How do you find the Z-score for a confidence level?
Divide α equally into both tails.
Look up the corresponding Z-score in a standard normal table.
When do we use the t-distribution instead of the Z-distribution?
When the sample size is small (n < 100) and population standard deviation (σ) is unknown.
How does the shape of the t-distribution compare to the Z-distribution?
The t-distribution has heavier tails, meaning more variability.
What happens to the width of a confidence interval as confidence level increases?
It widens.
What happens to the width of a confidence interval as sample size increases?
It narrows.
