please i need the correct answer

Add 9 and 13 to the distribution. O O O O O 8 O 5 6 A 7 8 9 10 11 12 13 14 15 16 17 18 O O O O 8 O 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Which one of the following best describes how the changes affect the mean and standard deviation? O The mean does not change. The standard deviation does not change. O The mean does not change. The standard deviation is smaller. The mean does not change. The standard deviation is larger, O The mean changes. The standard deviation does not change. O The mean changes. The standard deviation is smaller. O The mean changes. The standard deviation is larger