Astronauts often report episodes of disorientation as they move around the zero gravity spacecraft. To compensate, crew members rely heavily on visual information to establish a top-down orientation. An empirical study was conducted to assess the potential of using color brightness as a body orientation cue (Human Factors, Dec. 1988). Ninety college students, reclining on their backs in the dark, were disoriented when positioned on a rotating platform under a slowly rotating disk that filled their entire field of vision. Half the disk was painted with a brighter level of color than the other half. The students were asked to say “stop” when they believed they were right-side-up, and the brightness level of the disk was recorded. Of the 90 students, 58 selected the brighter color level.

a. Use this information to estimate the true proportion of subjects who use the bright color level as a cue to being right-side-up. Construct a 95% confidence interval for the true proportion.

b. Can you infer from the result, part a, that a majority of subjects would select bright color levels over dark color levels as a cue to being right-side-up? Explain.