What Factors Affect the Margin of Error? (In a Confidence Interval for One Mean) @jbstatistics

Uploaded May 2013 | Updated September 2026, 2 hours ago

A look at the effect of various factors (the standard deviation, the sample size, and the confidence level) on the margin of error of a confidence interval for the population mean.

For those that use R, below I give the R code to find the values given in this video.

Z value for a 90% interval (see my other videos for a more detailed explanation of the rationale):
qnorm(.95)
[1] 1.644854

Z value for a 95% interval:
qnorm(.975)
[1] 1.959964

Z value for a 99% interval:
qnorm(.995)
[1] 2.575829

What Factors Affect the Margin of Error? (In a Confidence Interval for One Mean)

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