chapter 6 (estimation for sample means/proportions)

Question 1

point estimate

Answer 1

estimate of population value where single value is specified.

Question 2

confidence intervals

Answer 2

estimate of population value in which a range of values is specified.

Question 3

margin of error

Answer 3

radius (half the size) of a confidence interval for a sample mean or sample proportion. aka: margin of sampling error or sampling error.

Question 4

bias

Answer 4

criterion used to select sample statistics as estimators. a statistic is unbiased if the mean of its sampling distribution is equal to the population value of interest.

Question 5

efficiency

Answer 5

extent to which the sample outcomes are clustered around the mean of the sampling distribution.

Question 6

alpha (α)

Answer 6

probability of error or probability that a confidence interval does not contain the population value. alpha levels usually set at 0.10, 0.05 (most common), 0.01, or 0.001.

Question 7

confidence level

Answer 7

frequently used alternative way of expressing alpha. probability that an interval estimate does contain the population value. confidence level usually set at 90%, 95% (most common), 99% or 99.9%.

Question 8

error bar

Answer 8

graphic display device used to illustrate the confidence interval of a sample statistic. based on upper and lower limits of ci.