Calculate the Sample Standard Deviation. 1  Calculate the mean or average of each data set. 2  To do this, add up all the numbers in a data set and divide by the total number of pieces of data. 3  For example, if you have found numbers in a data set, divide the sum by 4.alculate the Population Standard Deviation. 1  Calculate the mean or average of each data set. 2  Add up all the numbers in a data set and divide by the total number of pieces of data. 3  For example, if you have found numbers in a data set, divide the sum by 4.
Most pregnant women begin to show during the second trimester. You likely gained less than 5 pounds during your first trimester, but now the number on the scale is edging relentlessly upward. As your second trimester proceeds, you'll gain an average of 1 to 2 pounds per week.
With first time mothers, baby bumps start to show around week 12 of their pregnancy, or just as they enter their second trimester. This is the time when the baby rises out of the pelvis. However, this is not a rule. Some mothers get baby bumps sooner, some get them later. Also, some mothers try to disguise their bump.