Ten different families were tested for the average number of gallons of water they used per day before and after viewing a conservation video. A 90% confidence interval for the difference of the means after and before the training, was determined to be (−10.8,−4.2) a. Based on this sample, we are 90% confident that the average decrease in daily water consumption after viewing the conservation video is between 4.2 and 10.8 gallons.
b. We are 90% confident that a randomly selected family who has viewed the video will use between 4.2 and 10.8 fewer gallons of water per day compared to a randomly selected family who has not viewed the video.
c. We know that 90% of families will use between 4.2 and 10.8 fewer gallons of water each day after viewing the conservation video.
d. We are 90% confident that a randomly selected family who has viewed the video will use between 4.2 and 10.8 more gallons of water per day compared to a randomly selected family who has not viewed the video.
e. Based on this sample, we are 90% confident that the average increase in daily water consumption after viewing the conservation video is between 4.2 and 10.8 gallons.