answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
larisa [96]
2 years ago
9

Consider a disease whose presence can be identified by carrying out a blood test. Let p denote the probability that a randomly s

elected individual has the disease. Suppose n individuals are independently selected for testing. One way to proceed is to carry out a separate test on each of the n blood samples. A potentially more economical approach, group testing, was introduced during World War II to identify syphilitic men among army inductees. First, take a part of each blood sample, combine these specimens, and carry out a single test. If no one has the disease, the result will be negative, and only the one test is required. If at least one individual is diseased, the test on the combined sample will yield a positive result, in which case the n individual tests are then carried out. [The article "Random Multiple-Access Communication and Group Testing"† applied these ideas to a communication system in which the dichotomy was active/idle user rather than diseased/nondiseased.] If p = 0.15 and n = 5, what is the expected number of tests using this procedure? (Round your answer to three decimal places.)
Mathematics
1 answer:
kifflom [539]2 years ago
3 0

Answer:

The expected number of tests, E(X) = 6.00

Step-by-step explanation:

Let us denote the number of tests required by X.

In the case of 5 individuals, the possible value of x are 1, if no one has the disease, and 6, if at least one person has the disease.

To find the probability that no one has the disease, we will consider the fact that the selection is independent. Thus, only one test is necessary.

Case 1: P(X=1) = [P (not infected)]⁵

                       = (0.15 - 0.1)⁵

            P(X=1) = 3.125*10⁻⁷

Case 2: P(X=6) = 1- P(X=1)

                        = 1 - (1 - 0.1)⁵

               P(X=6) = (1 - 3.125*10⁻⁷) = 0.999999

               P(X=6) = 1.0

We can then use the previously determined values to compute the expected number of tests.

E(X) = ∑x.P(X=x)

      = (1).(3.125*10⁻⁷) + 6.(1.0)

 E(X)  =  E(X) = 6.00

Therefore, the expected number of tests, E(X) = 6.00

You might be interested in
Find the perimeter of △CDE. Round your answer to the nearest hundredth. The perimeter is about units.
Troyanec [42]

Answer: 9.66\ units

Step-by-step explanation:

The triangle CDE is shown in the image attached.

The formula for calculate the distance between two points is:

d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}

Then, we can calculate the lenght of each side of the triangle:

d_{CD}=\sqrt{(4-4)^2+(-5-(-1))^2}=4\ units\\\\d_{DE}=\sqrt{(4-2)^2+(-5-(-3))^2}=2.828\ units\\\\d_{CE}=\sqrt{(2-4)^2+(-3-(-1))^2}=2.828\ units

Therefore, the perimeter is:

P=4\ units+ 2.828\ units+2.828\ units=9.66\ units

8 0
1 year ago
Kirti knows the following information from a study on cold medicine that included 60 participants: 30 participants in total rece
GalinKa [24]
The frequency table is attached.

Since there were 30 people out of the 60 that received cold medicine, that means that 60-30=30 people did not.

Since 26 people had a cold longer than 7 days, this means 60-26=34 had a cold that was less than or equal to 7 days.

14 people had a cold longer than 7 days and received medicine; this means that 26-14=12 people had a cold longer than 7 days and did not receive medicine.

30-14=16 people received medicine and had a cold less than or equal to 7 days.

30-12=18 people did not receive medicine and had a cold less than or equal to 7 days.

4 0
2 years ago
J.J.Bean sells a wide variety of outdoor equipment and clothing. The company sells both through mail order and via the internet.
melamori03 [73]

Answer:

99% confidence interval for the true mean difference between the mean amount of mail-order purchases and the mean amount of internet purchases is [$(-31.82) , $12.02].

Step-by-step explanation:

We are given that a random sample of 16 sales receipts for mail-order sales results in a mean sale amount of $74.50 with a standard deviation of $17.25.

A random sample of 9 sales receipts for internet sales results in a mean sale amount of $84.40 with a standard deviation of $21.25.

The pivotal quantity that will be used for constructing 99% confidence interval for true mean difference is given by;

                      P.Q.  =  \frac{(\bar X_1-\bar X_2)-(\mu_1-\mu_2)}{s_p \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }  ~ t__n_1_+_n_2_-_2

where, \bar X_1 = sample mean for mail-order sales = $74.50

\bar X_2 = sample mean for internet sales = $84.40

s_1 = sample standard deviation for mail-order purchases = $17.25

s_2 = sample standard deviation for internet purchases = $21.25

n_1 = sample of sales receipts for mail-order purchases = 16

n_2 = sample of sales receipts for internet purchases = 9

Also,  s_p =\sqrt{\frac{(n_1-1)\times s_1^{2}+(n_2-1)\times s_2^{2} }{n_1+n_2-2} }  =  \sqrt{\frac{(16-1)\times 17.25^{2}+(9-1)\times 21.25^{2} }{16+9-2} } = 18.74

The true mean difference between the mean amount of mail-order purchases and the mean amount of internet purchases is represented by (\mu_1-\mu_2).

Now, 99% confidence interval for (\mu_1-\mu_2) is given by;

             = (\bar X_1-\bar X_2) \pm t_(_\frac{\alpha}{2}_)  \times s_p \times \sqrt{\frac{1}{n_1} +\frac{1}{n_2}}

Here, the critical value of t at 0.5% level of significance and 23 degrees of freedom is given as 2.807.

          = (74.50-84.40) \pm (2.807  \times 18.74 \times \sqrt{\frac{1}{16} +\frac{1}{9}})

          = [$-31.82 , $12.02]

Hence, 99% confidence interval for the true mean difference between the mean amount of mail-order purchases and the mean amount of internet purchases is [$(-31.82) , $12.02].

5 0
2 years ago
A recipe calls for 2 tsp of salt, 1 tsp of pepper, and 4 tsp of garlic powder. How much pepper and garlic powder would you need
MakcuM [25]

Answer:

amount of pepper required= 7.5 tsp

amount of garlic powder required = 30 tsp

Step-by-step explanation:

Given,

amount of salt used for small batch of the recipe = 2 tsp

amount of pepper used for small batch of the recipe = 1 tsp

amount of garlic powder used for small batch of the recipe = 4 tsp

amount of salt used for the larger batch = 15 tsp

                                                             = 2 x 7.5 tsp

                                                             = amount of salt used for small batch the recipe x 7.5

So,

the amount of pepper needed for the larger batch= 7.5 x amount of pepper used for the small batch of recipe

                                                                      = 7.5 x 1 tsp

                                                                       = 7.5 tsp

the amount of garlic powder needed for the larger batch= 7.5 x amount of garlic powder used for the small batch of recipe

                                                                                          = 7.5 x 4 tsp

                                                                                          = 30 tsp

3 0
2 years ago
On a coordinate plane, solid circles appear at the following points: (negative 4, 2), (negative 2, 2), (negative 1, 4), (1, 1),
Elenna [48]

Answer:

(1, 3)

Step-by-step explanation:

Given:

A circle with the following points on it-

(4, 2), (-2, 2), (-1, 4), (1, 1), (1, 3), (2, -3).

A function is just like a machine that gives an output for a given unique input.  No two outputs can have the same input.

The input to a function is called the domain of a given function. The output of a function is called its range.

The domain is represented by the 'x' coordinate and the range is represented by the 'y' coordinate.

So, the domain is the independent variable and range depends on the values of the domain.

Now, a relation of set of points represents a function only if all the 'x' coordinates of the set of ordered pairs are different.

Now, in the relation above, the ordered pairs (1, 1) and (1, 3) have the same input. So removing either of the two will make the relation a function.

So, the correct option is (1, 3).

5 0
1 year ago
Read 2 more answers
Other questions:
  • The annual salaries of all employees at a financial company are normally distributed with a mean= $34,000 and a standard deviati
    6·2 answers
  • Polygon ABCDE has the vertices A(2, 8), B(4, 12), C(10, 12), D(8, 8), and E(6, 6). Polygon MNOPQ has the vertices M(-2, 8), N(-4
    12·1 answer
  • mitch is buying candy bars for his friends. he wants to give 2 bars to each friend , and he wants to have 10 spare bares. he can
    10·1 answer
  • Evaluate log12y2, given log12y = 16. <br> 4 <br> 32 <br> 256 <br> 65,536
    11·2 answers
  • In the triangle m∠1 = 42°, and m∠4 =81°. What is m∠2°?
    10·1 answer
  • Find an upper limit for the zeroes 2x^4 -7x^3 + 4x^2 + 7x - 6 = 0
    7·1 answer
  • A point x is 34m due to east of a point Y . The bearing of a flagpole from x and Y are N18°W And N40°E respectively .
    10·1 answer
  • Solve for x in the equation x squared minus 14 x + 31 = 63.
    12·2 answers
  • fill in the table with whole numbers to make 2.8 in three different ways i do not get this qestion can you help me
    14·1 answer
  • Please help i don’t know how to do this
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!