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.
Second trimester Second trimester (13 to 27 weeks) Physical effects of pregnancy on you Your pregnancy will become more visible during your second trimester. Exactly when this happens varies from woman to woman, but most women look pregnant from around the 20th week of pregnancy.