The factors that affect the visibility of powered two-wheelers (ptws)long dashmotorcycleslong dashon the road were investigated in a study. a visual search study was conducted in which viewers were presented with pictures of driving scenarios and asked to identify the presence or absence of a ptw. of interest to the researchers is the detection rate, that is, the proportion of pictures showing a ptw in which the viewer actually detected the presence of the ptw. suppose that, in theory, the true detection rate for pictures of ptws is 0.72. the study revealed that in a sample of 2 comma 285 pictures that included a ptw, only 1 comma 540 were detected by the viewers. use this result to test the theory at alphaequals0.05.