Suppose on a specific street, the mean (average) speed of cars is 43 miles per hour and standard deviation 2.7 miles per hour.
Suppose 55 cars are randomly selected and the mean speed computed. Let it be X¯. The sampling distribution of X¯ follows Normal distribution.
Mean of X¯ is mph.
Standard deviation of X¯ is mph. Round to 2 decimals.
In the sample of 55 cars, what is the probability that the mean speed is between 42.5 and 43.5 miles per hour? Round to 2 decimal.
In the sample of 55 cars, what is the probability that the average speed is more than 44 miles per hour? Round to 3 decimals.