Question

In: Statistics and Probability

The football coach randomly selected ten players and timed how long each player took to perform...

The football coach randomly selected ten players and timed how long each player took to perform a certain drill. The times (in minutes) were:

7, 10, 14, 15, 15, 5, 12, 15, 11, 11

Find a 95 percent confidence interval for the population standard deviation.

Could someone show me how to do this? Please show work and answer

Solutions

Expert Solution

Here s = 3.4721 and n = 10
df = 10 - 1 = 9

α = 1 - 0.95 = 0.05
The critical values for α = 0.05 and df = 9 are Χ^2(1-α/2,n-1) = 2.7004 and Χ^2(α/2,n-1) = 19.0228

CI = (sqrt(9*3.4721^2/19.0228) , sqrt(9*3.4721^2/2.7004))
CI = (2.3882 , 6.3387)


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