and population mean, as do individual values, but the variance of sample means is smaller. The standard deviation measures variation of individual data values around the population mean, while the standard error measures variation of sample means around the population mean. In cell E$13,$ write a formula that calculates the standard error $($SE$)$ based on an assumed process mean of $400$ mm$,$ standard deviation of $2$ mm$,$ and sample of size $100.$