Homework Help: Probability-Math

Posted by Alia on Saturday, January 12, 2013 at 12:22am.

Please forgive me for posting this for the 3rd time but I really need to learn this:
A researcher conducted a study of the access speed of 45 hard drives and concluded that his maximum error of estimate was 28. If he were to conduct a second study to reduce the maximum error of estimate to 7, about how many hard drives should he include in his new sample?
Select one:
a. 720
b. 45
c. 90
d. 180
Please can someone explain me how to do the above problem.
My working: 28/7 = 4, so 4^2=16
16 x 45 =720.
I am not sure if the above working is correct but please i really need help in learning this problem (question). So, Please can anyone assist me by showing the correct method for this.
Thanks.

No one has answered this question yet.

Answer this Question

Related Questions

Intro to Probability, please check my work. - A fair coin is flipped three times...
math - please help!! - If rhys is late for his finite mathematics class, and the...
Probability. - Sorry for posting so many topics, but I really need help on this ...
Test tomm. Need help *Urgent* - Sorry for posting so many topics, but I really ...
math - You randomly draw letter tiles from a bag containing the letters from the...
PLz!!!My teacher gave me 10 more min.so plz help!! - I really need help!! My ...
AlgebraII - I really stuck on binomial theorem and I have a whole worksheet due ...
Math/Statistics - STATISTICS PLEASE HELP!!!!! I am sorry this is jy second time ...
Math - I need help with these three math question. 1st question. What is the ...
3rd grade - Please help me to rhyming words. The word is sleep. And I need to ...

For Further Reading

First Name:
School Subject:
Answer: