5-30-13
Standard Deviation
Standard Deviation- The standard deviation is a measure of how much scores differ from the mean.
Example
scores = 10,11,11,13,14,19; mean= 13; Deviation unit = 3; 5 in first group; 1 in second.
Steps:
Steps:
- calculate the mean
- subtract the mean from each number
- square the answer
- add all the squared numbers
- finish the formula
Experiment
Measure height:
Wesley: 175 cm
Matt: 159 cm
Ann: 171 cm
Miranda: 164 cm
Bass: 165 cm
Rishav: 179 cm
Average: 169 cm
Wesley: 175 cm - 169 cm = 6 squared = 36
Matt: 159 cm - 169 cm = -10 squared = 100
Ann: 171 cm - 169 cm = 2 squared = 4
Miranda: 164 cm - 169 cm = -5 squared = 25
Bass: 165 cm - 169 cm = -4 squared = 16
Rishav: 179 cm - 169 cm = 10 squared = 100
squared sum = 140 + 41 + 100 = 240 + 41 = 281/6 = 47 approx. square root = 7 cm.
level 1 = 162 - 176; level 2 = 155 - 183.
Wesley: 175 cm
Matt: 159 cm
Ann: 171 cm
Miranda: 164 cm
Bass: 165 cm
Rishav: 179 cm
Average: 169 cm
Wesley: 175 cm - 169 cm = 6 squared = 36
Matt: 159 cm - 169 cm = -10 squared = 100
Ann: 171 cm - 169 cm = 2 squared = 4
Miranda: 164 cm - 169 cm = -5 squared = 25
Bass: 165 cm - 169 cm = -4 squared = 16
Rishav: 179 cm - 169 cm = 10 squared = 100
squared sum = 140 + 41 + 100 = 240 + 41 = 281/6 = 47 approx. square root = 7 cm.
level 1 = 162 - 176; level 2 = 155 - 183.