Question 1: An automaker has found that the lifetime of its batteries varies from car to car according to a normal distribution with mean = 48 months and standard deviation = 8.2 months. The company installs a new battery on an SRS of 8 cars.

• Calculate the mean for the sampling distribution.
• Calculate the standard deviation for the sampling distribution
• Find the probability that the sample mean life is less than 42.2 months.

Question 2: The number of lightning strikes on a square kilometer of open ground in a year has a mean of 6 and a standard deviation of 2.4. The National Lightning Detection Network (NLDN) uses automatic sensors to watch for lightning in a random sample of fifty 1-square-kilometer plots of land. Let "x-bar" be the average number of lightning strikes in the sample.

Calculate the probability that the average number of lightning strikes per square kilometer is less than 5.

What was the z-score that you got to find this probability?

Question 3: What is the shape of the sampling distribution for samples of size n = 50 from this population?

• Right Skewed
• Left Skewed
• Approximately Normal
• Uniform

Question 4: What is the name of the theorem that allows us to state the shape?

• The IQR
• The CLT
• The BLT
• The SRS