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Confidence Intervals for Population Mean definitions

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  • Confidence Interval
    Range of values calculated from sample data that likely contains the true population mean at a specified confidence level.
  • Population Mean
    Average value for all members of a group, estimated using sample data and confidence intervals.
  • Sample Mean
    Average value calculated from a subset of the population, used as a point estimate for the population mean.
  • Margin of Error
    Amount added and subtracted from the sample mean to create the bounds of a confidence interval.
  • Critical Value
    Number from a statistical distribution used to determine the margin of error for a confidence interval.
  • Z Score
    Value from the standard normal distribution used when the population standard deviation is known.
  • T Score
    Value from the t distribution used when the population standard deviation is unknown and sample standard deviation is used.
  • Standard Deviation
    Measure of variability in a dataset, used in margin of error calculations for confidence intervals.
  • Sample Standard Deviation
    Estimate of variability within a sample, substituted for population standard deviation when unknown.
  • Population Standard Deviation
    True measure of variability for an entire population, used in z-based confidence intervals.
  • Degrees of Freedom
    Parameter for the t distribution, calculated as sample size minus one, affecting the shape of the distribution.
  • Confidence Level
    Probability that the calculated interval contains the true population mean, expressed as a percentage.
  • Alpha
    Probability of error in a confidence interval, equal to one minus the confidence level.
  • T Distribution
    Probability distribution used for confidence intervals when the population standard deviation is unknown.
  • Z Table
    Reference chart for finding critical z values based on desired confidence levels and probabilities.