11.2 Calculating the Mean and Standard Deviation

First, you will make a copy of the data on birthweight and sort the values from the smallest to the largest. Then you will calculate the mean and standard deviation. These Excel functions were covered in Lab 4 Measures of Central Tendency and Variation.

  1. Select the cells in Column B (cells B1:B1001).

Note: A shortcut to select data in a range, click on the first cell in the range and press the Shift + Arrow Down keys to select a range of data.

  1. Copy (CRTL-C on PC or Command-C on MAC) the selected data, click on cell J1 (or any empty cells of the worksheet), and Paste (CRTL-V on PC or Command-V on MAC) the data.
  2. Select the cells J1:J1001 (or the cells that contain the copy of the data). Go to Sort & Filter ribbon in the Home tab and select Sort Smallest to Largest.
  3. Type the label Mean in cell H1.
  4. Select cell H2, then enter the formula = AVERAGE(J2:J101).
  5. Adjust the mean value to one (1) decimal place.
  6. Type the label Stand Dev in cell H3.
  7. Select cell H4, then enter = STDEV(J2:J101).
  8. Adjust the standard deviation value to two (2) decimal places.

The data’s mean is 119.9, and the standard deviation is 17.99.