Understand and use the approximate confidence interval (x̄ − z s/√n, x̄ + z s/√n), as an interval estimate for μ, the population mean, where z is the appropriate quantile for the standard normal distribution.

u4-t5-s2-d2

Interactive

Confidence interval for a mean

manipulative

Sliders for n, confidence level (90/95/99%) and sample sd s show the margin of error and interval width around a fixed x̄, plus an E-vs-n curve.

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