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.
Another early sign of pregnancy is the change in colour of your vulva and vagina (Chadwick's sign). It can happen as early as four weeks of pregnancy, often before you notice other signs (Cunningham et al 2005 cited by Hassall and Murray 2009:220) .owever, at this stage, your doctor will say that you're four weeks pregnant. She'll count your pregnancy from the first day of your last period, because there's no way of knowing for sure the exact day that you conceived.