On a typical saturday, the oil-change facility will perform 40 oil changes between 10 a. m. and 12 p. m. treating this as a random sample, at what mean oil-change time would there be a 10% chance of being at or below? this will be the goal established by the manager.

chad should not have included the values (1, 2) and (3, 6) because that would mean he only had half a healing card.

b. 153 students do not participate in sports and seventy-five 12th graders were surveyed

85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560