Approximately 56% of the people wear seat belts. If 50 people were randomly checked, find the mean, variance, and standard deviation for how many will be wearing seat belts.
nA (E
Obns
Mean =
Variance =
Stand Dev =
Mean = 28
Variance = 16
Stand Dev = 4
1) To start her old lawn mower, Rita has to pull a cord and hope for some luck. On any particular pull, the mower has a 20% chance of starting.
a) Find the probability that it takes her exactly 3 pulls to start the mower.
b) Find the probability that it takes her 10 or fewer pulls to start the mower.
4) Marti decides to keep placing a $1 bet on number 15 in consecutive spins of a roulette wheel until she wins. On any spin, there's a 1-in-38 chance that the ball will land in the 15 slot.
a) How many spins do you expect it to take until Marti wins? Justity your answer.
b) What is the probability that it takes 5 spins before Marti wins?