Answer:
<h2>B. (2, 1)</h2>
Step-by-step explanation:
![\left\{\begin{array}{ccc}-3y=x-5&\text{subtract x from both sides}\\x+5y=7\end{array}\right\\\\\underline{+\left\{\begin{array}{ccc}-x-3y=-5\\x+5y=7\end{array}\right}\qquad\text{add both sides of the equations}\\.\qquad\qquad2y=2\qquad\text{divide both sides by 2}\\.\qquad\qquad y=1\\\\\text{Put the value of y to the second equation:}\\x+5(1)=7\\x+5=7\qquad\text{subtract 5 from both sides}\\x=2](https://tex.z-dn.net/?f=%5Cleft%5C%7B%5Cbegin%7Barray%7D%7Bccc%7D-3y%3Dx-5%26%5Ctext%7Bsubtract%20x%20from%20both%20sides%7D%5C%5Cx%2B5y%3D7%5Cend%7Barray%7D%5Cright%5C%5C%5C%5C%5Cunderline%7B%2B%5Cleft%5C%7B%5Cbegin%7Barray%7D%7Bccc%7D-x-3y%3D-5%5C%5Cx%2B5y%3D7%5Cend%7Barray%7D%5Cright%7D%5Cqquad%5Ctext%7Badd%20both%20sides%20of%20the%20equations%7D%5C%5C.%5Cqquad%5Cqquad2y%3D2%5Cqquad%5Ctext%7Bdivide%20both%20sides%20by%202%7D%5C%5C.%5Cqquad%5Cqquad%20y%3D1%5C%5C%5C%5C%5Ctext%7BPut%20the%20value%20of%20y%20to%20the%20second%20equation%3A%7D%5C%5Cx%2B5%281%29%3D7%5C%5Cx%2B5%3D7%5Cqquad%5Ctext%7Bsubtract%205%20from%20both%20sides%7D%5C%5Cx%3D2)
Answer:
The 95% Confidence Interval for the difference between the two population mean completion times =
(0.081, 1.919)
Step-by-step explanation:
Confidence Interval for difference between two means =
μ1 -μ2 ± z × √ σ²1/n1 + σ²2/n2
Where
μ1 = mean 1 = 12 mins
σ1 = Standard deviation 1 = 2 mins
n1 = 100
μ2= mean 2 = 11 mins
σ2 = Standard deviation 2 = 3 mins
n1 = 50
z score for 95% confidence interval = 1.96
μ1 -μ2 ± z × √ σ²1/n1 + σ²2/n2
= 12 - 11 ± 1.96 × √2²/100 + 3²/50
= 1 ± 1.96 × √4/100 + 9/50
= 1 ± 1.96 × √0.04 + 0.18
= 1 ± 1.96 × √0.22
= 1 ± 1.96 × 0.469041576
= 1 ± 0.9193214889
Confidence Interval
= 1 - 0.9193214889
= 0.0806785111
≈ 0.081
1 + 0.9193214889
= 1.9193214889
≈ 1.919
Therefore, the 95% Confidence Interval for the difference between the two population mean completion times =
(0.081, 1.919)
Answer:
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Answer: the first box put 2
The second box put 3
Step-by-step explanation:
i will explain in the comments below