# Question

Many states have attempted to reduce the blood- alcohol level at which a driver is declared to be legally drunk. There has been resistance to this change in the law by certain business groups who have argued that the current limit is adequate. A study was conducted to demonstrate the effect on reaction time of a blood- alcohol level of .1%, the current limit in many states. A random sample of 25 persons of legal driving age had their reaction times recorded in a standard laboratory test procedure before and after drinking a sufficient amount of alcohol to raise their blood alcohol to a .1% level. The difference (After – Before) in their reaction times in seconds was recorded as follows:

a. Graph the data and assess whether the population has a normal distribution.

b. Place a 99% confidence interval on both the mean and the median differences in reaction times of drivers who have a blood- alcohol level of .1%.

c. Is there sufficient evidence that a blood- alcohol level of .1% causes any increase in the mean reaction time?

d. Is there sufficient evidence that a blood- alcohol level of .1% causes any increase in the median reaction time?

e. Which summary of reaction time differences seems more appropriate, the mean or median? Justify your answer.

a. Graph the data and assess whether the population has a normal distribution.

b. Place a 99% confidence interval on both the mean and the median differences in reaction times of drivers who have a blood- alcohol level of .1%.

c. Is there sufficient evidence that a blood- alcohol level of .1% causes any increase in the mean reaction time?

d. Is there sufficient evidence that a blood- alcohol level of .1% causes any increase in the median reaction time?

e. Which summary of reaction time differences seems more appropriate, the mean or median? Justify your answer.

## Answer to relevant Questions

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