The final scores of games of a certain sport were compared against the final point spreads established by oddsmakers. The difference between the game outcome and point spread (called a point-spread error) was calculated for 230 games. The mean error is X_bar = -0.7. The population standard deviation of the point-spread error sigma = 14.1. Use this information to test the hypothesis that the true mean point-spread error for all games differs from 0. Conduct the test at alpha =0.01 and interpret the result.
Determine the null and alternative hypotheses.
The test statistic Z= ___ ?
What is the appropriate conclusion at alpha = 0.01?