You can use the following syntax to check your answers. Note the answers you get in R will not be EXACTLY the same you get by hand but they should be pretty close.

If you sample standard deviation s = 2 and the sample size = 35, and your confidence level is 95% this is how you can have R calculate a Confidence Interval for \(\sigma\).

conf_sig(s = 2, size = 35, conf = .95)
## [1] 1.617744 2.620404

9.3

5. left critical value=10.117 and right critical value=30.144

7. left critical value=9.542 and right critical value=40.289

9.

  1. lower bound=7.94, upper bound=23.66
  2. lower bound=8.59, upper bound=20.63, interval width increases.
  3. lower bound=6.61, upper bound=31.36, interval width increases.

11. We are 95% confident that the population standard deviation of the PH of rainwater in tucker county is between 0.226 and 0.542.

13. We are 90% confident that the population standard deviation of the repair costs of a low impact collision involving mini and micro vehicles is between $734.87 and $1657.5.