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2 years ago

Make ‘w’ the subject.

Mathematics

1 answer:

Romashka-Z-Leto [24]2 years ago

6 0

Answer:

w = (cv +dy) / (cb - ad)

Step-by-step explanation:

Multiply through by c

aw + y = c(bw + v) / d Multiply by d

d(aw + y) = c(bw + v) Remove the brackets

daw + dy = cbw + cv Subtract dy from both sides.

daw +dy - dy = cbw + cv -dy

daw = cbw + cv - dy Subtract cbw from both sides

daw - cbw = cbw - cbw + cv - dy

daw - cbw = cv - dy Isolate W on the left.

w(da - cb) = cv - dy Divide by cb - ad on both sides.

w = (cv - dy) / (ad - bc) Answer

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A new screening test for Lyme disease is developed for use in the general population. The sensitivity and specificity of the new

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Answer:

predictive value of a positive test = 18.18%

predictive value of a negative test = 94.03%

Step-by-step explanation:

Sensitivity = 60% = 0.6

Specificity = 70% = 0.7

Let True Positive = TP

True Negative = TN

False Negative = FN

$Sensitivity = \frac{TP}{TP + FN} \\0.6 = \frac{TP}{TP + FN} \\0.6TP + 0.6FN = TP\\0.4TP = 0.6FN\\TP = 1.5 FN$

$Specificity = \frac{TN}{TN + FP} \\0.7 = \frac{TN}{TN + FP} \\0.7TN + 0.7FP = TN\\0.7FP = 0.3 TN\\TN = 7/3 FP$

Prevalence = 10% = 0.1

Three hundred people are screened, $T_{total} = 300$

Total number of people having the disease, $T_{disease} = ?$

$Prevalence = \frac{T_{disease} }{T_{total} } \\0.1 = \frac{T_{disease} }{300 }\\T_{disease} = 30$

$T_{disease} = TP + FN\\30 = TP + FN$

But TP = 1.5 FN

30 = 1.5 FN + FN

30 = 2.5 FN

FN = 30/2.5

FN = 12

TP = 1.5 FN = 1.5 * 12

TP = 18

$FP + TN = T_{total} - T_{disease} \\FP + TN = 300 - 30\\FP + TN = 270\\FP + \frac{7}{3} FP = 270\\\frac{10}{3} FP = 270\\FP = 27 * 3\\FP = 81$

81 + TN = 270

TN = 189

To calculate the Predictive value of positive test (PPT)

$PPT = \frac{TP}{TP + FP} * 100\\PPT = \frac{18}{18+81} * 100\\PPT = \frac{18}{99} * 100\\PPT = 18.18 \%$

To calculate the Predictive value of negative test (PNT)

$PPT = \frac{TN}{FN + TN} * 100\\PPT = \frac{189}{189+12} * 100\\PPT = \frac{189}{201} * 100\\PPT = 94.03 \%$

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3 years ago

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Answer:

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Step-by-step explanation:

If you subtratct 13 from 36, you get 23.

If you multiply that times -3, you get -69.

(The way I got 23 was by dividing -69 and -3)

I hope this helped you even though it's late.

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3 years ago

In the early spring, the trout at Big Blue Lake swim at a depth of 30 feet below sea level. When the lake warms up in the summer

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3 years ago

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Answer:

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Step-by-step explanation:

Given –

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