Stats Help Needed?
Suppose that 78% of cell phone owners used their cell phone in store for guidance on purchasing decisions.
If 22 people are selected at random, what is the probability that
A. exactly 5 used their cell phone in store?
B. at least 12 used their cell phone in store?
C. more than 9 but at most 14 used their cell phone in store?
D. less than 16 used their cell phone in store?
- davidLv 73 weeks agoBest answer
This is a binomial problem ... p = 0.78, q = 0.22
A 22C5 p^5 q^17 = 5.037x10^-8
B. I'm not doing all these .. P(12) = 22C12 p^12 q^10
P(13) = 22C13 p^13 q^9
P(14) = 22C14 p^14 q^8 .... etc
last P(22) = 22C22 p^22 q^0
... after doing all, then add them to get the anwer
C. P(10) + ... thru P(14)
D .. I'll bet you can do this one ...