In: Math
After a group of (volunteer) experimental subjects achieved a specified blood alcohol level from consuming liquor, psychologists placed each subject in a room and threatened them with electric shocks. Using special equipment, the psychologists recorded the startle response time (in milliseconds) of each subject. The mean and standard deviation of the startle response times is 37.9 milliseconds and 12.4 milliseconds, respectively.
a. Without knowing the shape of the distribution of these response times, what is the interval that contains at least 75% of response times?
b. If you are told that the shape of the distribution of response times is normal,
i. What interval contains approximately 68% of startle response times?
ii. What interval contains approximately 95% of startle response times?
iii. What interval contains 99.7% (i.e., almost all) of startle response times?
iv. Approximately what percentage of startle response times fall below 25.5 milliseconds? HINT: Use the fact that a normal distribution is symmetric around the mean to answer this question.