help pls!

Question

In a prince market research survey of 2518 motorists, 252 said that they made an obscene gesture in the previous month.

a) If 1 of the surveyed motorists is randomly selected, what is the probability that this motorists did not make an obscene gesture in the previous month?

 

b) If 50 of the surveyed motorists are randomly selected without replacement, what is the probability that none of them made an obscene gesture in the previous month?

 

please show work!

Answer 1

a)

In a prince market research survey is conducted among 2518  motorists.

Out of 2518 motorists, 252 said that they made an obscene gesture in the previous month.

Thus, number of motorists did not make an obscene gesture in the previous month is .

Find the probability that this motorists did not make an obscene gesture in the previous month.

.

.

Answer 2

b)

In a prince market research survey is conducted among 2518  motorists.

Out of 2518 motorists, 252 said that they made an obscene gesture in the previous month.

Thus, number of motorists did not make an obscene gesture in the previous month is .

50 of the surveyed motorists are randomly selected without replacement.

All the  50 selections are independent and without replacement.

Probability of the first motorist that who did not make an obscene gesture in the previous month is  .

Probability of the second motorist that who did not make an obscene gesture in the previous month is  .

For independent events .

.

For larger values of the population size, sampling formula without replacement is .

Probability of 50 survveyed motorists who didnt made obscene gestures without replacement is 0.00486.

Comments

couldnt you just use .899 to the power of 50 to get .00488