A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 one year ago
I've got 2 questions that I'd appreciate some help with. I will grant a medal to those who help.
anonymous
 one year ago
I've got 2 questions that I'd appreciate some help with. I will grant a medal to those who help.

This Question is Closed

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0In a sample of 100 households, the mean number of hours spent on social networking sites during the month of January was 50 hours. In a much larger study, the standard deviation was determined to be 6 hours. Assume the population standard deviation is the same. What is the 98% confidence interval for the mean hours devoted to social networking in January?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0and Two studies were completed in Florida. One study in northern Florida involved 2,000 patients; 64% of them experienced flulike symptoms during the month of December. The other study, in southern Florida, involved 3,000 patients; 54% of them experienced flulike symptoms during the same month. Which study has the smallest margin of error for a 95% confidence interval?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@nincompoop @dan815 @jim_thompson5910 @ganeshie8

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4In a sample of 100 households, the mean number of hours spent on social networking sites during the month of January was 50 hours. In a much larger study, the standard deviation was determined to be 6 hours. Assume the population standard deviation is the same. What is the 98% confidence interval for the mean hours devoted to social networking in January? from that we can find n = 100 xbar = 50 sigma = 6

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4if the confidence level is 98%, then what is the critical value?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I'm not exactly sure honestly. If I were to be looking for critical value, how would I find it?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4do you have a calculator?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4a TI calculator?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4hit 2nd, then the vars key

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4scroll down to invNorm

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4dw:1435127861838:dw

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I just get x, y, z, t, and s. It's an online calculator.

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.498% confidence means that the area under the curve (shown below) is 0.98 dw:1435127873474:dw

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.41  0.98 = 0.02 0.02/2 = 0.01 is in the left tail dw:1435127929596:dw

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4so do you see how the area under the curve to the left of z = k is 0.99 ? dw:1435127996415:dw

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0alright, I see the curve

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4you said it's an online calculator?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4what's the link to it

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4ok that calculator won't work

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4use this instead http://onlinestatbook.com/2/calculators/inverse_normal_dist.html

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4well I mean use it to find the value of k in that drawing

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4type in the area of 0.98 then click "between" leave the mean and std dev as they are

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Thanks, I've been looking around you asked if I had a TI Calculator. I have a normal one but I guess that won't do. Alright, I've set it to .98. Now just set between to 6 and 50?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4if you have TI83 or higher, then you can use that

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0no, it's just the basic calculator, nothing like a scientific one.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I couldn't find anything to emulate TI83 or anything else

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4ok, anyways, use that link I gave you to get what you see in the attached image

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0alright, so 2.327 is the critical value, where would this come in?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4\[\large n = 100\] \[\large \overline{x} = 50\] \[\large \sigma = 6\] \[\large z_c = 2.327\] you will use the values above to construct the confidence interval (L,U) L = lower bound U = upper bound \[\Large L = \overline{x}  z_c*\frac{\sigma}{\sqrt{n}}\] \[\Large U = \overline{x} + z_c*\frac{\sigma}{\sqrt{n}}\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I got 48.60 and 51.40 (for future users)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0alright, as for the other question, would you like me to post it in a different question or would you like to help on this thread?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4either way is fine

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0alright, so that you won't have to go back up or anything : Two studies were completed in Florida. One study in northern Florida involved 2,000 patients; 64% of them experienced flulike symptoms during the month of December. The other study, in southern Florida, involved 3,000 patients; 54% of them experienced flulike symptoms during the same month. Which study has the smallest margin of error for a 95% confidence interval?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4Margin of Error (of a proportion): \[\Large z_c*\sqrt{\frac{\hat{p}(1\hat{p})}{n}}\] \(\Large z_c\) is the critical value (based on the confidence level) \(\Large \hat{p} \) is the sample proportion

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4also, n = sample size

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4use the link I gave you to find zc (now at 95% confidence)

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4the phat values are the percentages of people who got sick

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0alright so critical is at 1.96, for northern Florida I get 2.1% and southern Florida is 1.8%. Out of the options, both "The southern Florida study with a margin of error of 1.8%." and "The northern Florida study with a margin of error of 2.1%." although southern Florida was 1.78%

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4Northern Florida Margin of Error \[\Large \large E = z_c*\sqrt{\frac{\hat{p}(1\hat{p})}{n}}\] \[\Large \large E = 1.96*\sqrt{\frac{0.64(10.64)}{2000}}\] \[\Large \large E \approx 0.02103692753231 \approx 2.10\%\]  Southern Florida Margin of Error \[\Large \large E = z_c*\sqrt{\frac{\hat{p}(1\hat{p})}{n}}\] \[\Large \large E = 1.96*\sqrt{\frac{0.54(10.54)}{3000}}\] \[\Large \large E \approx 0.0178349230444 \approx 1.78\%\]  so you have them both correct

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0well, 50/50 chance of getting this right, thank you for your help again c:

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0gah, it wasn't northern florida with 2.1%, I guess it was southern florida with 1.8% ._.

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4The only difference I see is 1.78% and 1.8%

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4well they wanted the smallest margin of error

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.4sorry I forgot to mention that

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0it's alright, I got 80% of the questions completed correctly c:
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.