In a representative sample of 96 U.S. teenagers, 37.5% had shared their computer password with

a friend.

(a) Give a 95% confidence interval for the proportion of all U.S. teenagers who shared their

computer password with a friend.

(b) If a much larger sample were taken, then the interval would be

(i) wider (ii) narrower (iii) not enough information

(c) If a higher level of confidence were desired, then the resulting interval would be(i) wider

(ii) narrower (iii) not enough information

(d) Based on your interval in (a), can we assert that more than 35% of all U.S.

teenagers share their computer password with a friend?

(i) yes (ii) borderline (iii) no, not at all

(e) A test is carried out to see if the proportion of all teenagers who share their computer

password with a friend equals 0.35, against the alternative that the proportion is greater

than 0.35, and the P-value is found to be 0.30. This means that (choose one):

i. If the proportion of all teenagers who share their password is equal to 0.35, then 0.30

is the probability that a random sample of 96 teenagers would have a proportion

who share their passwords equal to 0.375.

ii. If the proportion of all teenagers who share their password is equal to 0.35, then 0.30

is the probability that a random sample of 96 teenagers would have a proportion

who share their passwords at least as large as 0.375.

iii. If the proportion of all teenagers who share their password is greater than 0.35, then

0.30 is the probability that a random sample of 96 teenagers would have a

proportion who share their passwords equal to 0.375.

iv. If the proportion of all teenagers who share their password is greater than 0.35, then

0.30 is the probability that a random sample of 96 teenagers would have a

proportion who share their passwords at least as large as 0.375.