Based on a random sample of 1140 adults, the mean amount of sleep per night is 7.96 hours. Assuming the population standard deviation for the amount of sleep per night is 1.6 hours, construct 95% confidence interval for the mean amount of sleep per night. a. (7.67, 8.05)
b. (7.87, 8.05)
c. (8.09, 9.12)
d. (7.87, 8.23)

at 95% confidence interval,  the mean amount of sleep per night is ( 7.87, 8.05 ).

Option b) (7.87, 8.05) is the correct answer.

Step-by-step explanation:

Given the data in the question;

sample size n = 1140

sample mean x" = 7.96

standard deviation σ = 1.6

At 95% confidence interval,

significance level ∝ = 1 - 95% = 1 - 0.95 = 0.05

∝/2 = 0.05 / 2 = 0.025

Z-Critical = = 1.96

Top get the Margin of error E;

E = × ( σ /√n )

we substitute

E = 1.96 × ( 1.6 /√1140 )

E = 0.09

So, At 95% confidence interval of the population mean is;

⇒ x" ± E

⇒ x" - E or x" + E

we substitute

⇒ 7.96 - 0.09, 7.96 + 0.09

⇒ 7.87, 8.05

Therefore, at 95% confidence interval,  the mean amount of sleep per night is ( 7.87, 8.05 ).

Option b) (7.87, 8.05) is the correct answer.

what is the approximate angle of acb if abc is 25cm and the length of segment bc is 15

step-by-step explanation:

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional