A Math Professor records his commuting time to work on 24 days, finds a sample mean of 12 mins 45 seconds and standard deviation of 55 seconds. Suppose a normal quintile plot suggests the population...

A Math Professor records his commuting time to work on24 days, finds a sample mean of 12 mins 45 seconds and standard deviation of55 seconds.  Suppose a normal quintile plot suggests the population is approximately normally distributed.

If we are interested in creating a 95% confidence interval for σσ, the population standard deviation, then:

a)  What are the appropriate χ2RχR2 and χ2LχL2 values, the Right and Left Chi-square values?

Round your responses to at least 3 decimal places.

 χ2R=χR2=

χ2L=χL2=

b)  Next we construct the appropriate confidence interval.

Complete the statements below (rounding each of your interval bounds to at least 3 decimal places):

Context: "We are  % confident that the true standard deviation of the professor's     time to work lies between   and  "

Confidence: "Also,   % confidence refers to the fact the best  % of unbiased simple     samples will produce an     containing the population standard    ."