Characteristics of a rockfall. Refer to the Environmental Geology (Vol. 58, 2009) simulation study of how far a block from a collapsing rock wall will bounce down a soil slope, Exercise 2.61 (p. 89). Rebound lengths (in meters)

were estimated for 13 rock bounces. The data are repeated in the table. A MINITAB analysis of the data is shown in the printout below.

10.94 13.71 11.38 7.26 17.83 11.92 11.87 LO6 5.44 13.35 4.90 5.85 5.10 6.77 ROCKS

a. Locate a 95% confidence interval for s2 on the printout.
Interpret the result.

b. Locate a 95% confidence interval for s on the printout.
Interpret the result.

c. What conditions are required for the intervals, parts a and

b, to be valid?

Transcribed Image Text:

Test and CI for One Variance: REB-LENGTH Method The chi-square method is only for the normal distribution. The Bonett method is for any continuous distribution. Statistics Variable N StDev Variance REB-LENGTH 13 4.09 16.8 95% Confidence Intervals Variable Method CI for StDev CI for Variance REB-LENGTH Chi-Square Bonett (2.94, 6.76) (2.97, 6.64) (8.6, 45.7) (8.8, 44.1)