I need to find the sample variance and sample standard deviation.I'm also confused about how to find the second midpoints.

Correct Calculate the sample variance and sample standard deviation for the following frequency distribution of heights in centimeters for a sample of 8-year-old boys. If necessary, round to one more decimal place than the largest number of decimal places given in the data. Heights in Centimeters Class Frequency 118.6 - 121.8 34 121.9 - 125.1 36 125.2 - 128.4 29 128.5 - 131.7 39 131.8 - 135.0 41 Copy [