A person takes a multiple-choice exam in which each question has five possible answers. Suppose that the person has no idea about the answers to three of the questions and simply chooses randomly for each one.

Required:
a. What is the probability that the person will answer all three questions correctly?
b. What is the probability that the person will answer exactly two questions correctly?
c. What is the probability that the person will answer exactly one question correctly?
d. What is the probability that the person will answer no questions correctly?
e. Suppose that the person gets one point of credit for each correct answer and that 1/3 point is deducted for each incorrect answer. What is the expected value of the person’s score for the three questions?

Answers

Answer 1

Answer:

a. 0.008 = 0.8% probability that the person will answer all three questions correctly.

b. 0.096 = 9.6% probability that the person will answer exactly two questions correctly.

c. 0.384 = 38.4% probability that the person will answer exactly one question correctly.

d. 0.512 = 51.2% probability that the person will answer no questions correctly.

e. The expected value of the person’s score for the three questions is -0.2.

Step-by-step explanation:

For each question, there are only two possible outcomes. Either the person answers it correctly, or they do not. The probability of a person answering a question correctly is independent of any other question. This means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

Each question has five possible answers.

Person has no idea which option is correct, so the probability of answering correctly is:

[tex]p = \frac{1}{5} = 0.2[/tex]

Three questions:

This means that [tex]n = 3[/tex]

a. What is the probability that the person will answer all three questions correctly?

This is [tex]P(X = 3)[/tex]. So

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 3) = C_{3,3}.(0.2)^{3}.(0.8)^{0} = 0.008[/tex]

0.008 = 0.8% probability that the person will answer all three questions correctly.

b. What is the probability that the person will answer exactly two questions correctly?

This is [tex]P(X = 2)[/tex]. So

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 2) = C_{3,2}.(0.2)^{2}.(0.8)^{1} = 0.096[/tex]

0.096 = 9.6% probability that the person will answer exactly two questions correctly.

c. What is the probability that the person will answer exactly one question correctly?

This is [tex]P(X = 1)[/tex]. So

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 1) = C_{3,1}.(0.2)^{1}.(0.8)^{2} = 0.384[/tex]

0.384 = 38.4% probability that the person will answer exactly one question correctly.

d. What is the probability that the person will answer no questions correctly?

This is [tex]P(X = 0)[/tex]. So

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 0) = C_{3,0}.(0.2)^{0}.(0.8)^{3} = 0.512[/tex]

0.512 = 51.2% probability that the person will answer no questions correctly.

e. Suppose that the person gets one point of credit for each correct answer and that 1/3 point is deducted for each incorrect answer. What is the expected value of the person’s score for the three questions?

The expected number of correct answer is:

[tex]E(X) = np = 3*0.2 = 0.6[/tex]

And the expected number of wrong answers is 3 - 0.6 = 2.4. So, the expected score is:

[tex]S(x) = 0.6 - \frac{2.4}{3} = 0.6 - 0.8 = -0.2[/tex]

The expected value of the person’s score for the three questions is -0.2.


Related Questions

Find the value of x.

Answers

Answer:

Hello! answer: 84

Step-by-step explanation:

This is 360 degrees therefore 84 is the answer

84 + 84 + 96 + 96 = 360 degrees

Calculate the total cost, total depreciation, and annual depreciation for the following assets by using the straight-line method. Cost Shipping Charges Setup Charge Total Cost Salvage Value Estimated Useful Life (years) Depreciation Total Annual
1. $5,600 $210 $54 ______ $600 6
2. $16,900 $310 0 ______ $1900 4

Answers

Answer:

a. For Asset 1, we have:

Total cost = $5,864

Total depreciation = $5,264

Annual depreciation = $877.33

b. For Asset 2, we have:

Total cost = $17,210

Total depreciation = $15,310

Annual depreciation = $3,827.50

Step-by-step explanation:

Note: The data in this question are merged together. They are therefore sorted before answering the question. See the attached pdf for the complete question with the sorted data.

Also note: See the attached excel file for the presentation of the data in the question with the answers (in bold red color).

The explanation of the answers is now given as follow:

Straight line method is a method of calculating depreciation and amortization of an asset by dividing the difference between the total cost and salvage value of an asset by its estimated useful life.

Therefore, wee have:

a. For Asset 1, we have:

Total cost = Cost + Shipping Charges + Setup Charge = $5,600 + $210 + $54 = $5,864

Total depreciation = Total cost - Salvage Value = $5,864.00 = $600 = $5,264

Annual depreciation = Total depreciation / Estimated Useful Life = $5,264 / 6 = $877.33

b. For Asset 2, we have:

Total cost = Cost + Shipping Charges + Setup Charge = $16,900 + $310 + $0 = $17,210

Total depreciation = Total cost - Salvage Value = $17,210 - $1,900 = $15,310

Annual depreciation = Total depreciation / Estimated Useful Life = $15,310 / 4 = $3,827.50

you spin the spinner once
What is P(5)?

Answers

0-10

A spinner is split into 11 different pieces so you are less likely to land on five than the other numbers.

The probability of getting 5 on spinner is 0.25.

What is the probability?

Probability can be defined as the ratio of the number of favourable outcomes to the total number of outcomes of an event.

We know that, probability of an event = Number of favourable outcomes/Total number of outcomes.

Given that, on the spinner there are four numbers {3, 4, 5, 6}.

Number of favorable outcomes = 1

Total number of outcomes = 4

So, P(5) = 1/4

= 0.25

Therefore, the probability of getting 5 on spinner is 0.25.

To learn more about the probability visit:

https://brainly.com/question/11234923.

#SPJ2

Tommy is putting a wooden frame around his living room stained glass window shown below. Before he can build the frame,
he needs to find the perimeter of the window.
7 feet
4 feet
If the rectangular window is 7 feet long by 4 feet wide, what is the perimeter of the window?
OA.
14 feet
ОВ.
28 feet
OC.
11 feet
OD
22 feet

Answers

The perimeter of window is 28 feet

What is the length of AB?

Answers

Answer:

B. 6

Step-by-step explanation:

We can see that through angles A and C that this triangle is an isosceles triangle. Knowing that, we can set up the equation 3x=4x-2. We can simplify by adding 2 two both sides. We get the equation 3x+2=4x. Then we subtract 3x from both sides. So therefore, 2=x. Length AB is 3x so we would do 2*3, which is equal to 6. So your answer would be B. 6.

how many pieces of jewelry could she buy?
A woman went to a departmental store's one-day sale. She bought five blouses for $30 each and a pair of shoes for $55. She also wanted to buy some jewelry. Each tom of jewelry was bargain priced at $11.50 each. If she brought $251 with her,
She could buy pieces of jewelry
Enter your answer in the answer box

Answers

150 + 55 = 205
11.50 x 4 = 46
205 + 46 =$251
She could buy 4 pieces of jewelry

Use the counting principle to determine the number of elements in the sample space. The possible ways to complete a true-false examination consisting of 26 questions.

Answers

Answer:

2^26

Step-by-step explanation:

For a true - false examination ; number of options or possible outcomes = 2

Number of questions = 26

Using the counting principle ; the number of elements in the sample space ;

(2 * 2 * 2 *... * 2) for the entire 26 questions

This is equivalent to : 2^26

2^26 = 67108864

what is the price of a mobile set whose marked priced is Rs.15000 and 13% vAT was levied after allowing 20%discount on it.​

Answers

Answer:

Rs. 18080

Step-by-step explanation:

Given :

Marked price = Rs. 20000

Discount = 20%

Discounted price = (100-20)% * marked price

Discounted price = 80% * 20,000 = Rs. 16,000

The VAT = 13%

VAT charge = 13% * 16,000 = Rs. 2080

Final price = discounted price + VAT charge

Final price = 16000 + 2080 = Rs. 18080

When evaluated, which expression has a result that is a rational number?

Answers

Answer:

√144 * 0.25 is rational!

Step-by-step explanation:

the equation of a straight line is 2y+6x=-8.find the gradient of the line​

Answers

Step-by-step explanation:

Y= mx + c

2y = 3x - 8

2y = -3× - 8 ( divide all yerms by two )

y = -3 × 4

2

y = -3

2

Find the area of each triangle
8 yd
8 yd

Answers

Answer:

Area of triangles 1 = 18 ft²

Area of triangles 2 = 16 in²

Area of triangles 3 = 90 yd²

Step-by-step explanation:

Given:

1] Height of triangle = 4 ft

Base of triangle = 9 ft

2] Height of triangle = 4 in

Base of triangle = 8 in

3] Height of triangle = 12 yd

Base of triangle = 15 yd

Find:

Area of triangles

Computation:

Area of triangles = (1/2)(Base)(Height)

Area of triangles 1 = (1/2)(4)(9)

Area of triangles 1 = 18 ft²

Area of triangles 2 = (1/2)(4)(8)

Area of triangles 2 = 16 in²

Area of triangles 3 = (1/2)(12)(15)

Area of triangles 3 = 90 yd²

Hello if you're able to answer this question help me and provide work as well, Thank you.

Answers

Answer:

answer is option B since they are in GM

Answer:

[tex]\text{b. }786,432[/tex]

Step-by-step explanation:

The [tex]n[/tex]th term of a geometric sequence is given by [tex]a_n=a_1\cdot r^{n-1}[/tex].

What we know:

[tex]a_1[/tex] is 3 [tex]r[/tex] is 2 (common ratio, each term is being multiplied by 2)

Substituting given values, we get:

[tex]a_{19}=3\cdot 2^{19-1},\\a_{19}=3\cdot 2^{18}=\boxed{\text{b. }786,432}}[/tex]

Which pair of angles are vertical angles?

A) B) C) D)

Answers

Answer:

Step-by-step explanation:

The angles opposite each other when two lines cross. They are always equal.

here,vertically opposite angles are

angle RQW and angle TQU

angle RQV ang angle SQU

angle SQR and angle UQV

angle WQV and angle SQT

I’m so horrible at math, please help

Answers

Answer: 23

=21 ÷(14-11)+2⁴
=21 ÷3+16
=7+16
=23

Explanation: Use PEMDAS to simplify the expression. Parentheses, exponents, multiply, divide, add, and subtract.

P - Parenthesis ( )

E - Exponents ²

M - Multiplication ×

D - Division ÷

A - Addition +

S - Subtraction -

Question : 21 ÷ (14 - 11) + 2⁴

1st step : Subtract the two numbers inside the Parenthesis

⇒   21 ÷ 3 + 2⁴

2nd step : Calculate the value of 2⁴ which is related to Exponents

⇒   21 ÷ 3 + 16

3rd step : Perform Division

⇒   7 + 16

4th step : Perform Addition

⇒   23

Answer: 23

Which of the following terms have a GCF of ? Select two options.

Answers

Answer:

hi please upload the photo so we can help :)

Answer:

A:12p^3r and D:54p^3

Step-by-step explanation:

PLEASE HELP!! WILL GIVE BRAINLEIST FOR AN ACTUAL Answer

Answers

72/360 = x/10pi

1/5 = x/10pi

x = 2pi

6.3 cm

Find the solution set of this inequality. Select
the correct graph.
|-8x+4|>12

Answers

Answer:

The first option is correct

Step-by-step explanation:

Hope it is helpful....

What is m∠CDE? pls help

Answers

Answer:

68

Step-by-step explanation:

∠ACB = ∠DCE

          = 180-92/2

          =44

∠CDE = 180 - 44 / 2

         68

Robin saved money during the months of July and August can some one help me

Answers

Step-by-step explanation:

(340*20)-3

HOPE IT HEPL U

How would I figure this out?

Answers

Answer:

IGJ=90-38

=52

answer is option c

In a petri dish, a certain type of bacterium doubles in number every 20
minutes
There were originally 8, or 23 bacteria in the dish. After 140 minutes, the
number of bacteria has doubled 7 times, multiplying by 27.
Now the population of bacteria is 23.27. Expressed as a power, how many
bacteria are in the petri dish after 140 minutes?
O A. 210
B. 410
C. 27
D. 221
SUBMIT

Answers

The answer is d
Yep

PLEASE HELP!!!
The number of adults who have seen a new family play at the local theater, measured in hundreds of people, is represented by the
function a (w) = -0.4w2 + 3w + 8, where w is the number of weeks since the play opened.
The number of children who have seen the same play, measured in hundreds of people, is represented by the function
c (w) = -0.3w2 + 2w + 13, where w is the number of weeks since the play opened.
What function, d (w). can be used to determine how many more children than adults have seen the play in any week?
d (w) = -0.1w2 + 5W + 21
d (w) = 0.1w2 – w+ 5
d (w) = -0.1w2 – w + 5
Od (w) = 0.1w2 + 5W + 5

Answers

Answer:

d (w) = 0.1w² – w+ 5

Step-by-step explanation:

d(w) = c(w) - a(w)

= -0.3w²+2w+13 -(-0.4w²+3w+8)

= -0.3w²+0.4w²+2w-3w+13-8

= 0.1w²-w+5

Answer:

d (w) = 0.1w2 – w+ 5

Step-by-step explanation:

I took the test

NO LINKS OR ELSE YOU'LL BE REPORTED! Only answer if you're very good at Math.

Let u= (5,-12) and c= -3.What is ||cu||?

A: 21

B: 51

C: 39

D: -39​

Answers

Answer:

CU=-3(5,-12)

CU=36-15

CU=21

The answer is A=21

Answer:

[tex]=21[/tex]

Correct option is A

Step-by-step explanation:

[tex]-3\left(5-12\right)\\Follow\:the\:PEMDAS\:order\:of\:operations\\\mathrm{Calculate\:within\:parentheses}\:\left(5-12\right)\::\quad -7\\5-12=-7\\=-3\left(-7\right)\\\mathrm{Multiply\:and\:divide\:\left(left\:to\:right\right)}\:-3\left(-7\right)\::\quad 21\\-3\left(-7\right)\\\mathrm{Apply\:rule\:}-a\cdot \left(-b\right)\:=\:a\cdot \:b\\-3\left(-7\right)=3\cdot \:7=21\\=21[/tex]

PROBLEM IS ABOVE PLEASE HELP

Answers

Answer:

A

Step-by-step explanation:

slant height of the exagon = side/2 * √3 = 2.5√3 cm

area of the hexagon = (side * slant height)/2 * 6 = (5 * 2.5√3)/2 * 6 = 64,951905 cm^2

Volume of the prism = area of the hexagon * height = 974,278579 cm^3

Volume of the cylinder = radius^2 *  pi * height = 36 * pi * 15 = 1.696,460033 cm^3

volume of the kaleidoscope = 722,181454 cm^3


Soda is sold in aluminum cans that measure 7 inches in height and 2.8 inches in diameter.
How many cubic inches of soda are contained in a full can?

Answers

Answer:

Volume of soda in soda can = 43.1 inches³ (Approx.)

Step-by-step explanation:

Given:

Height of soda can = 7 inches

Diameter of soda can = 2.8 inches

Find:

Volume of soda in soda can

Computation:

Radius of soda can = Diameter of soda can / 2

Radius of soda can = 2.8 / 2

Radius of soda can = 1.4 inches

Volume of soda in soda can = Volume of cylinder

Volume of soda in soda can = πr²h

Volume of soda in soda can = (3.14)(1.4)²(7)

Volume of soda in soda can = (3.14)(1.96)(7)

Volume of soda in soda can = 43.1 inches³ (Approx.)

The following data represent weights (pounds) of a random sample of professional football players on the following teams. san francisco 49ers and green bay packers

X1 = weights of players for the Dallas Cowboys
X2 = weights of players for the Green Bay Packers
X3 = weights of players for the Denver Broncos
X4 = weights of players for the Miami Dolphins
X5 = weights of players for the San Francisco Forty Niners

You join a Fantasy Football league and you are wondering if weight is a factor in winning Football games. At a 5% level of Significant, determine if the weights of football players on each of these teams is same or different?

Answers

Answer:

The answer is "272.02 ".

Step-by-step explanation:

Please find the complete solution in the attached file.

Find the LCM of the polynomials.
x² - x - 42
x2 + x - 56

Answers

Answer:

x^3+7x^2-50x-336 or (x-7)(x+6)(x+8)

Step-by-step explanation:

Factor each equation.

x^2-x-42= (x-7)(x+6)

x^2+x-56= (x-7)(x+8)

The common factor is (x-7), therefore the other factors of the expressions must multiply to find the common factor.

(x-7)(x+6)(x+8)=x^3+7x^2-50x-336.

Triangle GCH is similar to triangle DCE. Find CH

Answers

Answer:

x = 65

Step-by-step explanation:

if two triangles are similar then we can use the similarity ratio to find the length of CH

60/156 = x/169 cross multiply expressions

156x = 10140 divide both sides by 156

x = 65

Given r=3 and a center of (3,5)? Find the equation of the circle in standard and general form.

Answers

9514 1404 393

Answer:

(x -3)^2 +(y -5)^2 = 9x^2 +y^2 -6x -10y +25 = 0

Step-by-step explanation:

The standard form equation for a circle of radius r and center (h, k) is ...

  (x -h)^2 +(y -k)^2 = r^2

For radius 3 and center (3, 5), this is ...

  (x -3)^2 +(y -5)^2 = 9 . . . . standard form equation

Expanding this and subtracting the constant on the right gives ...

  x^2 -6x +9 +y^2 -10y +25 -9 = 0

  x^2 +y^2 -6x -10y +25 = 0 . . . . general form equation

A curve passes through the point ( 0 , 7 ) (0,7) and has the property that the slope of the curve at every point P P is twice the y y -coordinate of P P . What is the equation of the curve

Answers

Answer:

The equation for the curve is:

[tex]f(x) = 7*e^{2*x}[/tex]

Step-by-step explanation:

We know that for a curve defined as:

y = f(x)

The slope of the curve at the point x is:

y = f'(x)

where f'(x) = df(x)/dx

Here we know that we have a function that passes through the point (0, 7)

We also know that the slope of the curve at every point is twice the value of the y-coordinate. (remember that the y-coordinate is given by f(x))

Then we have two equations:

f(0) = 7

f'(x) = 2*f(x)

From the shape of the equation, we can assume than this is an exponential equation like:

[tex]f(x) = A*e^{k*x}[/tex]

Replacing that in the second equation, we get:

[tex]k*A*e^{k*x} = 2*A*e^{k*x}[/tex]

From that equation, we can conclude that k = 2

Then:

[tex]f(x) = A*e^{2*x}[/tex]

Now we can use the first equation:

f(0) = 7

With this, we can find the value of A.

[tex]f(0) = 7 = A*e^{2*0}\\7 = A*e^0 = A*1\\7 = A[/tex]

Then we can conclude that the equation for the curve is:

[tex]f(x) = 7*e^{2*x}[/tex]

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