Answer:
(369.4563 , 380.5437)
Explanation:
Given that,
z_c = 1.96 at 95% confidence ⇒ Z- critical value
n = 50
x - bar = 375
SD = 20
Margin of error, E = ?
[tex]E=\frac{z_c\times SD}{\sqrt{n} }[/tex]
[tex]E=\frac{1.96\times 20}{\sqrt{50} }[/tex]
E = 5.5437
Therefore,
95% CI:
= (375 - 5.5437, 375 + 5.5437)
= (369.4563 , 380.5437)
Hence, the 95% confidence interval to estimate the true cost of the microwave is (369.4563 , 380.5437).
