8.2 Confidence Interval for Mean Toby wants to know the average price of new cars at a particular dealearship. He randomly selects a sample of 30 cars and finds that the average price to be $20600$20600 with a standard deviation of $1440$1440. What is the 80% confidence interval for the mean price of cars at this particular dealership? a.) Which distribution table will be used to find the critical value and why?

• t-table because the population standard deviation is unknown
• t-table because the population standard deviation is known
• Z-table because the population standard deviation is unknown
• Z-table because the population standard deviation is known

b.) With 80% confidence, we can say the true population mean price of cars at this dealership is between $** and $** .