James Short (17081768), a Scottish optician, constructed the highest-quality reflectors of his time. It was with these

Question:

James Short (1708€“1768), a Scottish optician, constructed the highest-quality reflectors of his time. It was with these reflectors that Short obtained the following measurements of the parallax of the sun (in seconds of a degree), based on the 1761 transit of Venus. The parallax of the sun is the angle a subtended by the Earth, as seen from the surface of the sun. (See accompanying diagram.)

a. Determine whether an assumption of normality is reasonable. Explain.
b. Construct a 95% confidence interval for the estimate of the mean parallax of the sun.
c. If the true value is 8.798 seconds of a degree, what does the confidence interval suggest about Short€™s measurements?