The sales of a grocery store had an average of $8,000 per day. The store introduced several advertising campaigns in order to increase sales. To determine whether or not the advertising campaigns have been effective in increasing sales, a sample of 64 days of sales was selected. It was found that the average was $8,300 per day. From past information, it is known that the standard deviation of the population is $1,200. The correct null hypothesis for this problem is the daily average equals 8000 the daily average is greater than 8300 the daily average is less than or equal to 8000 the daily average is greater than 8000