Variance = (Standard Deviation)² = 5² = 25.

Total sum = Mean * Number of values = 20 * 10 = 200

Total sum = Mean * Number of values = 20 * 5 = 100

Variance is the square of the standard deviation. Therefore, variance = 5² = 25.

Variance is the square of the standard deviation. Therefore, variance = 10² = 100.

Standard deviation is the square root of variance. Therefore, SD = √25 = 5.

Total sum = Mean * Number of elements = 50 * 10 = 500.

The total sum is 500. Increasing one number by 10 gives a new total of 510. New mean = 510 / 10 = 51.

Total sum = Mean * Number of items = 12 * 6 = 72.

Total sum = Mean * Number of items = 12 * 6 = 72.

Total sum = Mean * Number of items = 12 * 8 = 96.

Total sum = Mean * Number of items = 25 * 12 = 300.

Total = Mean * Number of Items = 25 * 8 = 200.

Total sum = Mean * Number of elements = 30 * 6 = 180.

Total sum = Mean * Number of items = 50 * 5 = 250.

Mean = Total Sum / Number of Items. Therefore, Total Sum = Mean * Number of Items = 20 * 5 = 100.

Mean = Sum / 5. Therefore, Sum = Mean * 5 = 6 * 5 = 30.

Mean = n(n + 1) / (2n) = 10.\n\n(n + 1) / 2 = 10\n\n(n + 1) = 20\n\nn = 19.

Mean = n(n + 1) / (2n) = (n + 1) / 2 = 15. Therefore, n + 1 = 30, so n = 29.

Mean = (15 + 18 + 22 + x + 25) / 5 = 20. Solving gives x = 24.

Mode is the number that appears most frequently. Here, 3 appears twice, so mode = 3.

Arranging the data: 3, 5, 7, 9, 11. Median = 7.

For the median to be 8, x must be less than or equal to 8. The only value that satisfies this is 6.

Median is the middle value. Here, median = 9.

For the median to be 9, x must be 9. The ordered set is 3, 7, 9, 9, 15.

Removing 5, which is the mode, leaves 3 as the new mode since it appears twice.

The original mode is 4. Increasing it by 1 gives a new mode of 5.

Arranging the numbers: 3, 5, 7, 8, 12. The median is the middle number, which is 7.

The mode is 5, as it appears 3 times, more than any other number.

Probability of not A = 1 - P(A) = 1 - 0.4 = 0.6.