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Home Q & A Board Science-Related Homework Help Mathematics Statistics and Probability
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Biala Biala
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4 years ago
A food safety guideline is that the mercury in fish should be below 1 part per million​ (ppm). Listed below are the amounts of mercury​ (ppm) found in tuna sushi sampled at different stores in a major city. Construct a 95​% confidence interval estimate of the mean amount of mercury in the population. Does it appear that there is too much mercury in tuna​ sushi?
0.51, 0.75, 0.09, 0.87, 1.36, 0.57, 0.80
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wrote...
#1
Educator
4 years ago
Begin by finding the mean (\(mean=\overline{x}\))

Add 0.51, 0.75, 0.09, 0.87, 1.36, 0.57, 0.80 then divide the sum by 7 (given there are 7 measurements)

\(\overline{x}=0.70714285714286\) (keep 2 significant figures)

The standard deviation (we'll denote it as \(\sigma\)) can be calculated using your calculator:

\(\sigma =0.38767315639657\) (should be 2 significant figures)

UL/LL = means +/- standard deviation / sqrt(population size)

UL = \(0.707\pm \frac{0.387}{\sqrt{7}}\)

UL = \(0.85\)
LL = \(0.56\)

[0.56, 0.85]

No, given the range is less than 1. Hope that helps, and hope I'm right
wrote...
#2
Educator
4 years ago
If you like the answer, please mark it solved
Biala Author
wrote...
#3
4 years ago Edited: 4 years ago, Biala
It says that it is incorrect.
Post Merge: 4 years ago

It also has to be three decimal places.
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#4
Educator
4 years ago
I made a critical error, fixing it now!
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#5
Educator
4 years ago
UL/LL = means +/- (z-score @ 95%)[standard deviation / sqrt(population size)]

\(0.707\pm \left(1.96\right)\frac{0.387}{\sqrt{7}}\)

UL = \(0.994\)
LL = \(0.420\)

Try these instead, now to 3 significant figures

Answer is still no, because the range is less than 1

Hope this is right, been a while since I've done statistics
Biala Author
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#6
4 years ago
Thank you for the help but there was an error in the system and I guess it counted my attempt for a similar question and now I can't put anything in. I didn't even use all of my attempts so that's a bit of a bummer.
wrote...
#7
Educator
4 years ago
Honestly I panicked because I thought it was due @ 11:30, like before (I take half the blame Grinning Face with Smiling Eyes)
Biala Author
wrote...
#8
4 years ago
It's okay. You tried to help and that's what matters. I got most of the questions right too so it isn't that much of a loss. Thank you again! This forum is a lot of help.
Post Merge: 4 years ago

I will just mark it as solved.
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#9
Educator
4 years ago
welcome :-)
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