You are working for a company and they have an order of one million circuits. Th

Question

You are working for a company and they have an order of one million circuits. The want to find out the average height of these circuits. It is impossible for them to measure the height of all circuits so they get a sample of 1000 circuits out of 1 million circuits. The sample mean is 1 cm and standard deviation is 0.16cm. Find the followings: a) 95 percent confidence interval for the mean value of circuits height b) 90 percent confidence interval for the mean value of circuits height. c) Which one is wider and why?

Explanation / Answer

Here n=1000 so we will use z distribution

Here mean=1 and sd=0.16

a. For 95% z value is 1.96

So E=z*sd/sqrt(n)=0.01

Hence CI=mean+/-E=1+/-0.01=(0.99,1.01)

b. For 90% CI z value is 1.645

So E=0.008

Hence CI=1+/-0.008=(0.992,1.008)

c. 95% is wider as its width is 0.02 and 90% have 0.016 width

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.