The department of motor vehicles wants to check whether drivers have a slower reaction time after drinking two cans of beer. This was done by selecting a sample of 19 drivers and randomly assigning them to one of the two groups. The reaction times (measured in seconds) in an obstacle course are measured for a group of 10 drivers who had no beer. The other group of 9 drivers were given two cans of beer each and their reaction times on the same obstacle course are measured. Use “N” for no beer and “B” for two cans of beer. It was found that x̅N = 134 seconds and x̅B = 189 seconds. a) Suppose a 95% confidence interval was calculated to be (-12.05, -9.95). What is the correct interpretation of this confidence interval? Group of answer choices We are 95% confident that the true mean difference between the reaction time of those who had no beers and the reaction time of those who had two cans of beer lies between -12.05 and
The department of motor vehicles wants to check whether drivers have a slower reaction time after drinking two cans of beer. This was done by selecting a sample of 19 drivers and randomly assigning them to one of the two groups. The reaction times (measured in seconds) in an obstacle course are measured for a group of 10 drivers who had no beer. The other group of 9 drivers were given two cans of beer each and their reaction times on the same obstacle course are measured. Use “N” for no beer and “B” for two cans of beer. It was found that x̅N = 134 seconds and x̅B = 189 seconds.
a) Suppose a 95% confidence interval was calculated to be (-12.05, -9.95). What is the correct interpretation of this confidence interval?
We are 95% confident that the true
We are 95% confident that the true difference between the mean reaction time of those who drink no beers and the mean reaction time of those who drink two cans of beer lies between -12.05 and -9.95 seconds.
We are 95% confident that the true difference between the sample mean reaction time of those who had no beers and the sample mean reaction time of those who had two cans of beer lies between -12.05 and -9.95 seconds.
b) Referring to the confidence interval given in the previous question, what would be the correct decision to make for the test of hypotheses with H0: μN = μB vs. Ha: μN ≠ μB at α = 0.05?
If the mean reaction time of those who had two cans of beer is slower than the mean reaction time of those who had no beers, the probability of obtaining a difference of 134-189 = -55 seconds or more extreme is 0.014.
The probability that the mean reaction time of those who had two cans of beer is slower than the mean reaction time of those who had no beers is 0.014.
The probability that the mean reaction time of those who had no beers is the same as the mean reaction time of those who had two cans of beer is 0.014.
If the mean reaction time of those who had no beers is the same as the mean reaction time of those who had two cans of beer, the probability of obtaining a difference of 134-189 = -55 seconds or more extreme is 0.014.
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