A Designer for a Rapid-Transit Commuter Train Was Working on a Double

A designer for a rapid-transit commuter train was working on a double safety system to stop the train in case of emergency. Much of the decision making was taken care of by a computer (how fast, where to stop, when to start slowing down, and so forth). Under some conditions a panic stop was called for (another train on the track ahead, for example). In such a case, the brakes were activated by the computer but, should this fail, the operator was to pull the brake lever. The question facing the de-signer was whether to make the signal for a panic stop auditory, visual, or a combination of both. The cost of each system was quite high. In order to decide, she looked up some old psychology studies on reaction times (RT). The following are RT scores (in seconds) to the three kinds of stimulus conditions. Perform an F test and, follow it up with any HSD tests necessary to help you interpret the results. Construct a summary table and explain the results with the terms used in the experiment. Use six decimals or convert all scores to whole numbers by multiplying the raw scores by 100. $$\begin{array} { c r c } \text { Auditory } & \text { Visual } & \text { Auditory and Visual } \\\hline .18 & .19 & .16 \\.20 & .24 & .18 \\.17 & .21 & .20 \\.18 & .20 & .15 \\.19 & .23 & .18 \\.20 & .22 & .17 \\.15 & .19 & \\.15 & &\end{array}$$