Q1) In standard normal distribution the variance is always.
Q2) Auditor wishes to evaluate what proportions of bank's commercial loan files are incomplete. Auditor randomly samples 100 files and determines 9 are incomplete. Using 95% confidence interval, evaluate true proportion of incomplete files for ALL the bank's commercial loans.
Q3) Determine P(9 < x < 15) when mu = 12 and sigma = 2. Write down your steps in probability notation.
Q4) Automobile safety engineer wishes to evaluate mean cost to repair a Chevy Corvette involved in a 30 mile per hour head-on collision. Engineer crashes 20 Corvettes and determine mean damage is $16,300 with standard deviation of $2,330. Determine a 95% confidence interval for true mean cost to repair this type of car.