48. What is the variance? A. 30.85 B. 39.71 C. 41.25 D. 43.4 49. What is the mean of the grouped data? A. 97 B. 128 C. 134 D. 154 50. Which of the following is the standard deviation? A. 4.67 B. 5.78 C. 6.30 D. 7.25​