Lifetimes of Wristwatches A random sample of the lifetimes of 30 inexpensive wristwatches has a standard deviation of 4.5. months. Assume the variable is normally distributed. Use the chi-square distribution table to find any chi-square values to three decimal places. Round your final answers to one decimal place.. Part: 0/2 Part 1 of 2 Find the 99% confidence intervals for the variance and standard deviation.