Answer:
The variance is of 8
Step-by-step explanation:
To find the variance and the standard deviation, first we need to find the mean.
Mean:
Sum of all values divided by the number of values. So
[tex]M = \frac{78+72+68+73+75+69+74+73+72}{9} = 72.67[/tex]
The standard deviation is of 2.83
Variances:
Sum of the difference squared between each value and the mean, divided by the number of values. So
[tex]V = \frac{(78-72.67)^2+(72-72.67)^2+(68-72.67)^2+(73-72.67)^2+(75-72.67)^2+(69-72.67)^2+(74-72.67)^2+(73-72.67)^2+(72-72.67)^2}{9} = 8[/tex]
The variance is of 8
Standard deviation:
Square root of the variance. So
[tex]S = \sqrt{V} = \sqrt{8} = 2.83[/tex]
The standard deviation is of 2.83
