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3 years ago

URGENT HELP PLZ

Mathematics

1 answer:

Aliun [14]3 years ago

8 0

Answer:

y = 1/3x + 4

Step-by-step explanation:

Slope-Intercept Form: y = mx + b

Slope Formula: $m=\frac{y_2-y_1}{x_2-x_1}$

Step 1: Find slope <em>m</em>

m = (2 - 3)/(-6 - -3)

m = -1/(-6 + 3)

m = -1/-3

m = 1/3

y = 1/3x + b

Step 2: Find y-intercept <em>b </em>(plug in coordinates)

3 = 1/3(-3) + b

3 = -1 + b

b = 4

Step 3: Rewrite linear equation

y = 1/3x + 4

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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

Anit [1.1K]

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)

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

7 0

3 years ago

Which is the side length of a cube with a volume of 1331 m3?

suter [353]

Let's remember the equation for the volume of a cube:
V= x^3 where x is the length of one side
Since a cube has equal length for length, width, and height.

Now, use what you're given
V= 1331

And put that in terms of x
x^3 = 1331

Now solve for x!
x= cube root (1331)

Think about it! cube root of 1331 * cube root of 1331 * cube root of 1331... will equal 1331 m^3!

Hope this helps

8 0

3 years ago

When two equal forces are inclined at an angle 2a their resultant is twice as great as

swat32

Step-by-step answer:

Referring to the attached diagram, the resultant of two forces each with magnitude F and inclined to each other at 2a equals

Ra = 2Fcos(a) ..............................(1)

Similarly, the resultant of two forces each with magnitude F and inclined to each other at 2b equals

Rb = 2Fcos(b)..............................(2)

We are given that

Ra = 2Rb ....................................(3)

Substitute (1) & (2) in (3) gives

2Fcos(a) = 2(2Fcos(b))

Expand

2Fcos(a) = 4Fcos(b)

Simplify

cos(a) = 2 cos(b) QED

Note: Please note that you might have a faster response if you posted this question in the physics or the (new) Engineering section.

Have a nice day!

5 0

3 years ago

3) The sum of two numbers is 17. The difference between five times the first number and three times

Nitella [24]

Answer:

8 and 9.

Step-by-step explanation:

Let the two unknown numbers be a and b.

When added together, they equal 17. In other words:

a + b = 17.

The <em>difference</em> between five times the first number and three times the second number is 13. In other words:

5a - 3b = 13.

We have a system of equations. We can use substitution. From the first equation, we can derive a = 17 - b. Let's substitute this in:

5(17 - b) - 3b = 13

85 - 5b - 3b = 13

-8b = -72

b = 9

a = 17 - b.

a = 17 - 9 = 8.

Thus, the two numbers are 8 and 9.

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3 years ago

The sum of three consecutive odd numbers is 159.<br> What is the smallest of the three numbers ?

natta225 [31]

Since we don't know where to start, we can always give that a variable which in this case, it's X. Since we are finding the sum of three consecutive odd numbers, we will be skipping numbers so we can add 2 each time. Now, let's set up an equation.

<h2>X + X + 2 + X + 4 = 159</h2><h2 /><h2>3x + 6 = 159</h2><h2> -6 -6 ← subtract 6 on both sides</h2><h2 /><h2> 3x = 153</h2><h2> ÷3 ÷3 ← divide both sides by 3</h2><h2 /><h2> X = 51</h2><h2> X + 2 = 53</h2><h2> X + 4 = 55</h2><h2 />

Therefore, the smallest of our three consecutive integers is 51.

6 0

3 years ago