Question

Automobile manufacturers are interested in the difference in reaction times for drivers reacting to traditional incandescent lights and to LED lights. A sample of 18 drivers are told to press a button as soon as they see a light flash in front of them and the reaction time was measured in milliseconds. Each driver was shown each type of light. The average difference in reaction times (traditional - LED) is -1.3 ms with a standard deviation of 5.83 ms. A 95% confidence interval for the average difference between the two reaction times was (-4.2, 1.6). Which of the following is the best interpretation?

Question 11 options:

	1) We are 95% confident that the average difference in reaction time between the two light types for all drivers is between -4.2 and 1.6.
	2) We are 95% confident that the average difference in the reaction times of the drivers sampled is between -4.2 and 1.6.
	3) The proportion of all drivers that had a difference in reaction times between the two lights is 95%.
	4) We are 95% confident that the difference between the average reaction time for LED lights and the average reaction time for traditional lights is between -4.2 and 1.6.
	5) We are certain the average difference in reaction times between the two light types for all drivers is between -4.2 and 1.6.

Answer 1

Option 4) is correct.

4)	We are 95% confident that the difference between the average reaction time for LED lights and the average reaction time for traditional lights is between -4.2 and 1.6.