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