The probability distribution for number of new android apps launched in a week during the year 2009 are as follows:
Number of Apps Probability (number of Apps=x)
20 0.15
25 ?
30 0.30
35 0.20
a) What is the probability that at most 25 apps were launched? (Hint: You need to find the ?)
b) Find the mean number of apps launched in a week.
c) Find the standard deviation.