What's the answer for K+4<11

What situation is an example of an observational study

If f(x) = 2x + 8 and g(x) = x4, what is (gº)?

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?