9. Calculate the mean number of children per family for the sample from the following table. (2 marks) Number of Children Number of families 0 8 1 16 2 22 3 14 4 6 5 4 6 2 a. 1.91 b. 2.47 c. 3.14 d. 2.19 e. None of the above 10. Which of the following data sets has the largest standard deviation? a. 2, 3, 4, 5, 6 b. 105, 110, 115, 120, 125 c. 301, 304, 306, 308, 311 d. 352, 354, 355, 356, 357 e. 888.1, 888.5, 888.6, 888.7, 888.9 11. The duration of youtube commercials is normally distributed with a mean of 75 seconds and a standard deviation of 20 seconds. What is the probability that a commercial at the start of your video will last less than 35 seconds or more than 87 seconds? (2 marks) a. 0.4772, 0.0228 b. 0.9772, 0.5228 c. 0.0228, 0.2257 d. 0.0228, 0.2743 e. 0.5228, 0.2743 12. On an exam with a mean of 70, you have a score of X = 65. Which of the following values for the standard deviation would give you the best standing within the class? a. SD=1 b. SD=5 c. SD=10 d. It cannot be determined from the information given