8.6. Refer to Exercise 8.5. Compute 10-year increments of the population growth x1 = 5.3−3.9, x2 = 7.2 − 5.3, etc. (a) Compute sample mean, median, and variance of 10-year increments. Discuss how the U.S. population changes during a decade. (b) Construct a time plot of 10-year increments and discuss the observed pattern.

8.6. Refer to Exercise 8.5. Compute 10-year increments of the population growth x1 = 5.3−3.9,
x2 = 7.2 − 5.3, etc.
(a) Compute sample mean, median, and variance of 10-year increments. Discuss how the
U.S. population changes during a decade.
(b) Construct a time plot of 10-year increments and discuss the observed pattern.

a)  Mean = 13.88

Median = 13

Variance= 87.6035

Note: The rate of change is increasing after each decade. 

b)