Question

The diameter of a ring is known to have a normal distribution with standard deviation of
0.05 inch. A random sample of 20 rings have an average diameter of 2.1015 inch. What is
the 95% two-sided confidence interval for the population mean diameter of rings.​

Answer 1

$\fontsize{18}{10}{\textup{\textbf{The required interval is 2.0795 to 2.1234}}}$Step-by-step explanation:

The below is the required two sided confidence interval for the population mean dianmeter of rings

(2.1015-1.96*0.05/rt20) to (2.1015+1.96*0.05/rt20)  (mean+-z-score*s.d./rt(n))

where

sample mean=2.1015

z-score=1.96 for 95% confidence or 5% significance level

standard deviation=0.05

n=20

rt=square root

So the required interval is 2.0795 to 2.1234

Answer 2

Answer:

Step-by-step explanation: