Question: According to a recent poll by the Pew Internet Project, girls between the ages of 14 and 17 send an average of 187 text messages each day. Let X = the number of texts that a girl aged 14 to 17 sends per day. The discrete random variable X takes on the values x = 0, 1, 2. The random variable X has a Poisson distribution: X ~ P(187). The mean is 187 text messages.
a. What is the probability that a teen girl sends exactly 175 texts per day?
b. What is the probability that a teen girl sends at most 150 texts per day?
c. What is the standard deviation?