3. When the variance is equal to zero... a the standard deviation is equal to 1 b the raw scores are negative c all of the raw scores are the same d the variance can never be equal to zero 4. Two samples are as follows Sample A: 7 9 10 9 12 Sample B: 13 5 9 17 9 4A. Just by looking at these data, which sample has more variability? 4B. What is the mode for sample A? 4C. What is the mean for sample B? 4D. What is the range for sample A? 4E. What is the median for sample B? 4F. What is the standard deviation for sample A (use computational formula)?_ 4G. What is the variance for sample B (use computational formula)