Chapter 7: Confidence Intervals Flashcards
What is a confidence interval?
Specifies range of values to estimate location of unknown pop parameter
What does the margin of error accompany?
Confidence level
What does the confidence level tell us?
How likely our parameter is to lie within that interval
What does the confidence level and margin of error together tell us?
How accurate our estimate is likely to be
What is a point estimate?
Single statistic used as best estimate or a alike parameter
What does accuracy refer to?
Freedom from error
What is freedom from error?
Estimate differs from parameter of interests value
What is the interval estimate?
Range of values parameter is likely to fall
What is the essence of sampling theory?
Probability sample will yield results that closely resemble those if we measured whole pop
What is a probability sample?
Every element known prob of being selected
What does the law of large numbers tell us?
With large sample, sample statistics approximate pop parameters very closely
What does a confidence level specify?
Probability that our particular sample will contain pop parameter
What happens with higher confidence levels?
lower the risk that interval estimate doesn’t have parameter
What happens with a lower confidence level?
Increases risk interval estimate doesn’t have parameter
What happens in the case of the 99% confidence interval?
99% of all samples drawn from the same population with same measure at same time will be ± amount of sampling error