Uploaded January 2014 | Updated September 2026, 1 hour ago
A brief introduction to measures of central tendency. The mean, median, and mode are introduced and calculated for a simple example. The relationship between the mean and median for different shapes of distributions is then discussed.
The guinea pig survival time data can be found in:
Doksum, K. (1974). Empirical probability plots and statistical inference
for nonlinear models in the two-sample case. Annals of Statistics, 2:267--277.
A brief introduction to measures of central tendency. The mean, median, and mode are introduced and calculated for a simple example. The relationship between the mean and median for different shapes of distributions is then discussed.
The guinea pig survival time data can be found in:
Doksum, K. (1974). Empirical probability plots and statistical inference
for nonlinear models in the two-sample case. Annals of Statistics, 2:267--277.
![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 What Factors Affect the Margin of Error? (In a Confidence Interval for One Mean)](https://i.ytimg.com/vi/NQtcGOhUWB4/mqdefault.jpg)









