Question

1. Paris Saint-Germain, a French professional soccer team, led the 2015 ESPN/Sporting Intelligence Global Salary Survey with the largest payroll for all professional sports teams. A soccer fan looks up the salaries for all of the players on the 2015 Paris Saint-Germain team. Because the fan took a statistics course, the fan uses all of these salaries to get a 95% confidence interval for the mean salary for all 2015 Paris Saint-Germain players. This makes no sense. Why not? (2 pts)

Answer 1

Confidence Intervals are constructed for the estimation of the interval where the true value of the parameter lies with certain confidence based on the random samples of some fixed size. Here the fan does not took random samples from the salaries of all the players on the 2015 PSG team to calculate the confidence Interval. Instead he took the whole population and calculated the true value of the population mean, hence confidence interval for the mean makes no sense.