Violins Stradivarius violins, made in the 1700s by a man of the same name, are worth millions of dollars. They are prized by music lovers for their uniquely rich, full sound. In September 2009, an audience of experts took part in a blind test of violins, one of which was a Stradivarius. There were four other violins (modern day instruments) made of specially treated wood. When asked to pick the Stradivarius after listening to all five violins, 39 got it right and 113 got it wrong (Time magazine, November 23, 2009).
a. If this group were just guessing, how many people (out of the 152) would be expected to guess correctly? And how many would be expected to guess incorrectly?
b. Calculate the observed value of the chi-square statistic showing each step of the calculation.