3. Suppose, the social network estimates the average number of duplicate accounts is 11 of monthly active users. Suppose X is the randomly selected account. a. What is the distribution X ? Give a justification of your answer.  b. What is the probability that fewer than two accounts are duplicate in a randomly selected accounts among the monthly active users?  c. What is the probability that exactly none of the accounts are duplicate in a randomly selected accounts among the weekly active users? d. Find the (Mean ± Standard deviation) interval for monthly active users and hence comment this interval.

A box contains the following tickets: 1, 1, 1, 1, 2, 2, 3, 3. Which of the plots below represents the probability histogram for a single draw from this box?   (a) (b) (c)

a Sample Percent approve Percent disapprove Figure 3.11 a. Define three events in the graph. b. Describe in words what the entry 40 means. c. Describe in words the complement of the entry in question 2.

6. Employers often require their employees to be subjected to random drug testing. Suppose that 5% of employees use a certain type of drug. Drug testing accuracy varies. From years of data collection it is known that those who use this type of drug have ½ 94% chance of testing positive. It is also known that 3% of non-drug users (of the certain type of drug) still test positive. a.) Fill out a probability cross tabulation. b.) If the employee tests positive for a certain drug, what's the probability that the employee uses the drug? c) If the employee tests positive for a certain drug, what's the probability that the employee does NOT use the drug?