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9 Cards in this Set
 Front
 Back
point estimate

single value (or point) used to approximate a population parameter


confidence interval

interval estimaterange of values used to estimate the true value of a population parameter


confidence level

probability 1alpha that is the proportion of times that the confidence interval actually does contain the population parameter, assuming that the estimation process is repeated a large number of times


critical value

number on the borderline separating sample statistics that are likly to occur from those that are unlikely to occur, the number z alpha/2 is a critical value that is a z score with the property that it seperates an area of alpha/2 in the right tail of the standard normal distribution


margain of error

when data form a simple random sample are used to estimate a population proportion p the margin of error, denoted by E, is the maximum likely difference between the observed sample proportion p hat and the true value of the population proportion p, the margin of error E is also called the maximum error of the estimate and can be found by multiplying the critical value and the standard deviation of sample proportions


round off rule for confidence interval estimates of p

round the confidence interval limits for p to three significant digits


round off rule for determining sample size

in order to ensure that the required sample size is at least as large as it should be, if the computed sample size is not a whole number, round it up to the next higher whole number


requirements for estimating mu when sigma is unknown

1. the sample is a simple random sample
2. either the sample is from a normally distributed population or n greater than 30 

degrees of freedom

collection of sample data is the number of sample values that can vary after certain restrictions have been imposed on all data values
