A poll agency reports that

38

%

of teenagers aged

12

17

own smartphones. A random sample of120

teenagers is drawn. Round your answers to at least four decimal places as needed.

Part 1 of 6

Your Answer is correct

(a) Find the mean

p

.The mean

p

is0.38

.

Part 2 of 6

Your Answer is incorrect

(b) Find the standard deviation

p

.The standard deviation

p

is45.6

.

Correct Answer:

0.0443

Part 3 of 6

Your Answer is correct

(c) Find the probability that more than40

%

of the sampled teenagers own a smartphone.The probability that more than40

%

of the sampled teenagers own a smartphone is0.3264

.

Part:3 / 6

3 of 6 Parts Complete

Part 4 of 6

Your Answer is incorrect

(d) Find the probability that the proportion of the sampled teenagers who own a smartphone is between0.35

and0.45

.The probability that the proportion of the sampled teenagers who own a smartphone is between0.35

and0.45

is

45.6

.