The standard deviation of 15 scores was 5 and the mean was 85. What was the variance? In a set of 22 scores in statistics, the highest and the lowest scores were found to 89 and 25 respectively. The...

Extracted text: The standard deviation of 15 scores was 5 and the mean was 85. What was the variance? In a set of 22 scores in statistics, the highest and the lowest scores were found to 89 and 25 respectively. The 5th, 6th, 11th, 12th, 16th and 17th scores were 31, 35, 54, 56, 78 and 80 respectively. Find the passing mark if half of the students failed the test.