Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p. of 140 adults selected randomly from one town, 35 of them smoke. construct a 99% confidence interval for the true percentage of all adults in the town that smoke.
a)15.6% b)16.5% c)19.0% d)17.8%

CI = (0.156, 0.344)

Step-by-step explanation:

Confidence interval = proportion ± margin of error

CI = p ± ME

The proportion is:

p = x / n

p = 35/140

p = 0.25

Margin of error = critical value × standard error

ME = CV × SE

n > 30, so we can approximate CV with a normal distribution.  At P = 99%, CV = 2.576.

SE = √(pq / n)

SE = √(0.25 (1 − 0.25) / 140)

SE = 0.037

So the margin of error is:

ME = 2.576 × 0.037

ME = 0.094

So the confidence interval is:

CI = 0.25 ± 0.094

CI = (0.156, 0.344)

idk

step-by-step explanation:

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9