PLEASE HELPPPPPPPPPPPPPPPPPPPP ME HAS CONFUSION

A common blood test performed on pregnant women to screen for chromosome abnormalities in the fetus measures the human chorionic

goldfiish [28.3K]

Answer:

(a) The proportion of women who are tested, get a negative test result is 0.82.

(b) The proportion of women who get a positive test result are actually carrying a fetus with a chromosome abnormality is 0.20.

Step-by-step explanation:

The Bayes' theorem states that the conditional probability of an event E $_{i}$ , of the sample space S, given that another event A has already occurred is:

$P(E_{i}|A)=\frac{P(A|E_{i})P(E_{i})}{\sum\liits^{n}_{i=1}{P(A|E_{i})P(E_{i})}}$

The law of total probability states that, if events E₁, E₂, E₃... are parts of a sample space then for any event A,

$P(A)=\sum\limits^{n}_{i=1}{P(A|B_{i})P(B_{i})}$

Denote the events as follows:

X = fetus have a chromosome abnormality.

Y = the test is positive

The information provided is:

$P(X)=0.04\\P(Y|X)=0.90\\P(Y^{c}|X^{c})=0.85$

Using the above the probabilities compute the remaining values as follows:

$P(X^{c})=1-P(X)=1-0.04=0.96$

$P(Y^{c}|X)=1-P(Y|X)=1-0.90=0.10$

$P(Y|X^{c})=1-P(Y^{c}|X^{c})=1-0.85=0.15$

(a)

Compute the probability of women who are tested negative as follows:

Use the law of total probability:

$P(Y^{c})=P(Y^{c}|X)P(X)+P(Y^{c}|X^{c})P(X^{c})$

$=(0.10\times 0.04)+(0.85\times 0.96)\\=0.004+0.816\\=0.82$

Thus, the proportion of women who are tested, get a negative test result is 0.82.

(b)

Compute the value of P (X|Y) as follows:

Use the Bayes' theorem:

$P(X|Y)=\frac{P(Y|X)P(X)}{P(Y|X)P(X)+P(Y|X^{c})P(X^{c})}$

$=\frac{(0.90\times 0.04)}{(0.90\times 0.04)+(0.15\times 0.96)}$

$=0.20$

Thus, the proportion of women who get a positive test result are actually carrying a fetus with a chromosome abnormality is 0.20.

6 0

3 years ago

How many faces does the solid made from the net below have?

nikdorinn [45]

Answer:We need to see the net.

Step-by-step explanation:

5 0

3 years ago

PLEASE HELP! I WILL MARK TOU AS BRAINLEIST!

san4es73 [151]

Answer:

a.Z(-2,1)

b.Z(1,1)

c.Z(-3,2)

Step-by-step explanation:

z(-2,3)

Imagine this point on a graph.

Translate it down two units :

the x stays -2, by going down the y decreases 2 so 3-2=1

Z(-2,1)

Translate Right three units : I'm assuming that we use the answer from the first translation

Z(-2,1)

The y doesn't change this time the x increases 3 since we're moving to the right.

Z(1,1)

Translate up 1 and left 4:

Z(1,1)

by moving up one we have Z(1,2) then by moving 4 to the left we get Z(-3,2)

Hope this helps :)

6 0

3 years ago

Read 2 more answers

A jar contains 8 red marbles, 10 blue marbles, and 2 yellow marbles. One marble is chosen at random. The color is recorded in th

NeX [460]

Answer:

blue is more likely to be chosen because there are more of them than the other colors

Step-by-step explanation:

6 0

3 years ago

A fisherman uses a spring scale to weigh a tilapia fish. He records the fish weight as a kilograms and notices that the spring s

belka [17]

Answer:

k = $\frac{980a}{b}$

Step-by-step explanation:

Fisherman noticed a stretch in the spring = 'b' centimetres

Weight of the fish = a kilograms

If force applied on a spring scale makes a stretch in the spring then Hook's law for the force applied is,

F = kΔx

Where k = spring constant

Δx = stretch in the spring

F = weight applied

F = mg

Here 'm' = mass of the fish

g = gravitational constant

F = a(9.8)

= 9.8a

Δx = b centimetres = 0.01b meters

Therefore, 9.8a = k(0.01b)

k = $\frac{9.8a}{0.01b}$

k = $\frac{980a}{b}$

Therefore, spring constant of the spring will be determined by the expression, k = $\frac{980a}{b}$

4 0

3 years ago