Pls hurry and show work will give brain liest

Airline passengers arrive randomly and independently at the passenger-screening facility at a major international airport. the mean arrival rate is 10 passengers per minutes. compute the following probabilities. p(x = 4) p(x > 11)

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

True or false: the graph of y=f(bx) is a horizontal compression of the graph y=f(x) if b< 1