A health magazine reported that 27% of adult males smoke cigarettes. A competing magazine thinks this claim is false. To test this claim, they select 40 adult males at random and record if they smoke cigarettes. They calculate a 95% confidence interval for the proportion of adult males who smoke and find it is 0.22 to 0.28. (a) Interpret the confidence interval.
(b) Calculate the point estimate and margin of error used to create this confidence interval.

Point estimate:
Margin of error:

(c) Based on the confidence interval, is it plausible that the true proportion of adult males who smoke cigarettes is 27%? Explain.

a) what is the point estimate used to create this confidence interval?

[a] 0.22

[b] 0.28

[c] 0.26

[d] 0.25  <

b) what is the margin of error used to create this confidence interval?

[a] .06

[b] .03    <

[c] .035

[d] .055

c) based on the confidence interval, it is plausible that the true proportion of adult males who smoke cigarettes is 27%?

[a] yes   <

[b] no

Step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15