Answer:
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 [tex]Z_{\alpha /2[/tex] = [tex]Z_{0.025[/tex] = 1.96
Top get the Margin of error E;
E = [tex]Z_{\alpha /2[/tex] × ( 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.
