Chi-square test for goodness of fit.
For many years TV executives used the guideline that 30 percent of the audience were watching each of prime-time networks and 10 percent were watching cable stations on a weekday night. A random sample of 500 viewers in the Tampa-St. Petersburg, Florida, and area last Monday night showed that 165 homes were tuned in to the ABC affiliate, 140 to the CBS affiliate, 125 to the NBC affiliate, and remainder were viewing a cable station. At the .05 significance level, can we bring to a close that the guideline is still reasonable?