A random sample of 16 statistics examinations from a large population was taken. The average score in the sample was 78.6 with a standard deviation of 8. We are interested in determining whether the average grade of the population is significantly more than 75. At significance level 0.05, it can be concluded that O we don't have enough evidence to determine that the average grade of the population is significantly more than 78.6. O we don't have enough evidence to determine that the average grade of the population is significantly more than 75. O is significantly greater than 78.6. the average grade of the population is significantly greater than 75.