The given numbers are daily groundwater elevation readings from a monitoring well taken during a month experiencing snowmelt and extended rainfall events.
7.6 7.7 4.3 5.9 5.0 10.5 7.7 9.5 12.0 12.6 6.5 8.3 8.2 13.2 12.6 13.6 14.1 13.5 11.5 12.0 10.4 10.8 13.1 12.5 10.4 13.0 14.1 15.1
What is the sample variance of these groundwater elevation readings?
A)8.764
B)9.089
C)10.56
D)None of the above

Question

Quizplus · Accepted Answer

The sample variance of the groundwater elevation readings is 9.089. Solution Use the sample variance (s 2 ) equation s 2 = ?(sample value - sample mean)2/(number of samples-1) Where Number of samples = 28 Sample mean = ?(sample values)/number of samples = 295.7/28 = 10.56 ?(sample value - sample mean) 2 = (7.6-10.56)2+(7.7-10.56) 2 + …… = 245.4 s 2 = 245.4/27 = 9.089

The Given Numbers Are Daily Groundwater Elevation Readings from a Monitoring