Chapter 6 Flashcards
Point estimate
An estimate of a population value where a single value is specified
Confidence intervals
An estimation of a population value in which a range of values a specified
Margin of error
The radius or half the size of a confidence interval for a sample mean or sample proportion.
Bias
A criterion used to select sample statistics as estimators. A statistic is unbiased, if the meaning of its sampling distribution is equal to the population value of interest.
Efficiency
The extent to which the sample outcomes are clustered around the mean of the sampling distribution
Alpha
The probability of error or the probability that a confidence interval does not contain the population value
Confidence level and example
A frequently used alternative way of expressing alpha. The probability that an interval estimate does not contain the population value value example is 95%.
Student T distribution
A distribution used in the construction of confidence intervals when the population standard deviation is unknown
Error bar
A graphic display device used to illustrate the confidence interval of a sample statistic
Point estimate and example
Sample statistic used to estimate a population parameter
Ex: 30% or 0.30
Confidence intervals and example
Consist of a range of values instead of a single point
Ex: between 27% and 30%
If n is large sample mean/proportion is equal to
The population parameter
The smaller the SD of a sampling distribution
The greater the clustering and higher efficiency
How to construct a confidence interval
Set alpha
Did z-score that goes with alpha
Use ci formula
When can you use t distributions
When not given the SD and you have a large sample
