1. Find X A. 16.45 B. 15.92 C. 12 D. 11.5

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

2 years ago

ike tossed a coin several times and recorded the number of heads and tails in the following table: Coin Experiment Side of Coin

UkoKoshka [18]

The correct answer is 0.48 because as you can tell the probability of it landing on heads is just a little bit below the probability of getting tails. Hope I helped!

8 0

2 years ago

Can someone help me wit #4 plzz

iris [78.8K]

Answer: It represents the area of the two circular sides ("lids")

Explanation:

Imagine you made a cylinder out of 3 pieces of paper. The cylinder can be decomposed into two circular shapes (radius r) and one rectangular piece with two side lengths: one is "h", the other has to be long enough to go around each of the disks, so it has to be 2*pi*r long.

So the term 2*pi*r*h is the area of the rectangular piece and pi*r^2 is the area of each of the "lids" Since there are two of those, the term 2*pi*r^2 represents the area of the bottom and top lids.

7 0

2 years ago

THIS IS 100 POINTS SOMEBODY PLEASEEEEEEEEEEEEEE HELP MEEEEE

Nookie1986 [14]

Answer: Option #4: the 0.2 could be changed to 2.

Explanation:

The table is designed to make the concept of percentages more understandable. The table first allocates the total amount of 70 in terms of its "fifths," or 20% parts. Then it expresses these parts in the last row of the table, showing that 20% of 70 is 14 and all the five parts sum up to 70 again.

Now, Mikel is supposed to express 40% of the amount. So she writes (incorrectly): 0.2 * 14. This statement needs to be changed to 2 * 14 (two times 14 = 28), to correspond to 2 times 20%, or 40% of 70.

This is reflected in the last (fourth) option "The 0.2 in the expression could be changed to 2."

Option #3 is incorrect because changing 14 to 70, will result in an incorrect number (2.8).

Options 1 and 2 are similarly incorrect (as can be easily verified)

3 0

2 years ago

Read 2 more answers

Use the drawing tools to form the correct answer on the number line.

Ainat [17]

Answer:

In the picture

Step-by-step explanation: