Lighter cars are more fuel-efficient than heavier cars. An environmentalist would like to estimate the true mean weight of all cars. To do so, she selects a random sample of 30 cars and determines the 90% confidence interval for the true mean weight to be 2.8 to 3.4 tons. Which of these statements is a correct interpretation of the confidence level? There is a probability of 0.90 that the confidence interval (2.8, 3.4) captures the true mean weight of all cars.
The environmentalist can be 90% confident that the true mean weight of all cars is between 2.8 and 3.4 tons.
If many random samples of size 30 are selected from the population of all cars, approximately 90% of the sample means will be between 2.8 and 3.4 tons.
If many random samples of size 30 are selected from the population of all cars, about 90% of the intervals would capture the true mean weight of all cars.