Layla guesses on all 20 questions of a multiple-choice test. Each question has 4 answer choices. What is the probability of a success and a failure for this experiment?

Answers

Answer 1

Step-by-step explanation:

what is the criteria for success ? how many questions must be right ? and how many must be wrong for failure ?

if success means all answers right, then she has 4 choices on the first question to pick one right answer. and then for each of those again 4 choices on the second question and so on.

so, all possible outcomes are 4²⁰.

that means the probability to guess all 20 right is

1/4²⁰

a tiny, tiny number.

and the probabilty to have all wrong ?

she has 4 choices to pick 1 of 3 wrong answers.

so, the probability is 3/4 to answer the first question wrong.

for that she has again then the same chance to get the second question wrong too.

so, it is 3/4 × 3/4 = 9/16

and so on.

the probability to guess all 20 wrong is then

(3/4)²⁰ ≈ 0.0032

that is still a small number but much, much larger than the probability to get everything right.

still, even the goal to truly get everything wrong is highly unlikely.


Related Questions

Don’t understand this problem

Answers

Answer: I'm not Einstein sorry

Step-by-step explanation:

Have to be smart as Einstein.................Which I'm not

What is the range of the function?
{(1.2, 11.6), (3.6, 11.5), (1.9, 11.4), (2.7, 11.5)}


Answers

Answer:

Range: 10.4

Step-by-step explanation:

Range = maximum(xi) - minimum(xi), where xi represents the set of values

= 11.6 -  1.2

= 10.4

Answer:

Range-

{

11.6

,

11.5

,

11.4

}

Step-by-step explanation:

help, please!
find x

Answers

This shape consists of two primary special triangles, 30-60-90 and 45-45-90.

the side with the 60° will be half of the hypotenuse because 30° is across from it.

the side with the 30° will be 5.5√3 because 60° is across from it, and any sides that has 60° across from it is associated with a √3.

x is 5.5√6 because any sides that is "below" the 45° angles are associated with a √2 times the side that's above the 45°

Pls halppppppppppppppp

Answers

Addition expression: -6 + 14 = 8

-6 because it’s below street level.

Answer:

-6 + 14

8

Step-by-step explanation:

Given: Hank is -6 below feet. He rises +14 feet above level.

-6 + 14 = 8

Addition expression: -6 + 14

Sum: 8

Hope this helped.

Where r is the radius of the cone's base and h is the height of the cone. Find the approximate volume of a
cone when r is 4 inches and his 3 inches.



Use volume of cone formula

Answers

Answer:

The volume of this cone is V = 50 (~50.27)

(I'm assuming that 'his' is height?)

Answer: 50

Step-by-step explanation:

10 cows, 26 horses and 4 goats are in a paddock. What is the percentage of animals that are horses?

Answers

Answer:

65% of the animals are horses

Step-by-step explanation:

10 cows + 26 horses + 4 goats = 40 animals

Since we’re looking for what percentage of animals are horses:

26(horses)/40(animals) = ?/100%

Divide 26 by 40

0.65

Multiply 0.65 by 100

26/40 = 65%/100%

Answer:

10+26+4=40

in total there is 40 animals

because there is in total for 40 animals then that mean 40 animals is 100%

now we see that there are 26 horses we only need to divid ( but remember you have to divid the percent and the number of animals together)

40 ÷ 20 = 2.    2 x 13 = 26

100% ÷ 20 = 5%.  5% x 13 = 65%

the answer for this question:

the percentage of animals that are horses is 65%


How many times greater is
3.8 X 10^5 than
1.9 X 10^2
2
20
200
2000

Answers

Answer:

2 * 10^3 = 2000.

Step-by-step explanation:

3.8/1.9 * 10^5/10^2

= 2 * 10^3

2000 is the answer

1.9 x 10^2= 190
3.8 x 10^5= 380000

Answers:
x2= 380
x20= 3800
x200= 38000
x2000= 380000

Correct Answer: 2000

Solve by completing the square. 2x^2 – 2x – 4 = 0

Answers

Step-by-step explanation:

Factor out 2,

- x - 2 = 0

- x = 2

- x + (-1/2)² = 2 + (-1/2)²

(x - 1/2)² = 9/4

x = ±3/2 + 1/2

x = 2 or x = -1

An urn has 6 white balls and 4 orange balls if Sam chooses 5 balls at random from the urn what is the probability that he chooses 2 white balls and 3 orange balls

Answers

Answer:

probability of picking white is 6/10

and probability of picking orange is 4/10

Step-by-step explanation:

so probability of picking 2 white and 3 orange will be 9/25 + 64/100 = 8/125

Which of the following theorems verifies that ANPO- AXYZ?

Answers

AA, cause they’ve given you two angles already
AA, both angles were given

In a study on the time that
a student required to obtain a college degree is randomly selected to 80
students and it is discovered that they have an average of 4.8 years (according to data from the National
Center for Education Statistics). Assuming s 2.2 years, construct an estimate of a confidence interval of the population mean. The confidence interval
the result contradicts the fact that 39% of students get their college degree in four years?

Answers

The 95% confidence interval of the population mean, in years, is (4.3, 5.3). 4 years is not part of the confidence interval, which means that it contradicts the fact that 39% of students get their college degree in four years.

-----------------------------

To solve this question, we need to find the confidence interval for the amount of time it takes the students to get the degree.

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

-----------------------------

The first step to solve this problem is finding how many degrees of freedom,which is the sample size subtracted by 1. So

df = 80 - 1 = 79

-----------------------------

95% confidence interval

Standard level of confidence, we have to find a value of T, which is found looking at the t table, with 79 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.95}{2} = 0.975[/tex]. So we have T = 1.9905.

-----------------------------

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 1.9905\frac{2.2}{\sqrt{80}} = 0.5[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

-----------------------------

The lower end of the interval is the sample mean subtracted by M. So it is 4.8 - 0.3 = 4.3 years.

The upper end of the interval is the sample mean added to M. So it is 4.8 + 0.3 = 5.3 years.

-----------------------------

The 95% confidence interval of the population mean, in years, is (4.3, 5.3). 4 years is not part of the confidence interval, which means that it contradicts the fact that 39% of students get their college degree in four years.

A similar question is given at https://brainly.com/question/24278748

Can anyone help me with this answer?

Answers

9514 1404 393

Answer:

  D

Step-by-step explanation:

Do this multiplication the same way you would for integers. The "place value" of a column is the power of x for that column.

The sum of partial products matches answer choice D.

_____

Additional comment

We used a spreadsheet because it provides a nice grid for aligning rows and columns. If you want to have the spreadsheet do the multiplication and sum, you need to leave out the variables. Here, we did the multiplication and sum mentally and used the spreadsheet simply to record the result.

0.3,1/5,1/2,0.706,7/8,57.1%
Place following in ascending order

Answers

Answer:

the answer is 0.31/ 5.1/8.57.1% /207067

Step-by-step explanation:

ascending order from the smallest to the largest

Josh has 4 times as many pears as leya, who has one half as many pears as amy. If josh has 32 pears how many does amy have?

Answers

Answer:

josh = 32

leya = 8

amy =4

Step-by-step explanation:

32 pears

Josh = 4l

leya = a/2

Amy = ?

L =8

A = 4

Check answer:

josh = 32

leya = 8

amy =4

Josh has 4 times as Leya True

Leya has half as many pears as Amy True

The number of pears Amy has is 16.

Step-by-step explanation:

Let J represent the number of pears Josh has.

Let L represent the number of pears Leya has.

Let A represent the number of pears Amy has.

From the question given above,

Josh (J) = 4 × Leya (L)

J = 4L ....... (1)

Leya (L) = ½ × Amy (A)

L = ½A ........ (2)

Next, we shall determine the number of pears Leya has. This can be obtained as follow:

From equation 1

J = 4L

But

Josh (J) = 32 pears

Thus,

32 = 4L

Divide both side by 4

L = 32 / 4

Leya (L) = 8 pears

Finally, we shall determine the number pears Amy has. This can be obtained as follow:

From equation 2

L = ½A

But

Leya (L) = 8 pears

Thus,

8 = ½A

Cross multiply

A = 8 × 2

Amy (A) = 16 pears

Therefore, Amy has 16 pears.

Learn more: https://brainly.com/question/20971657

Indigo Company had cash sales of $78,120 (including taxes) for the month of June. Sales are subject to 8.5% sales tax. how to record the sale ?

Answers

Answer:

Step-by-step explanation:

Sales revenue x (100%+sales tax rate) = total sales including tax

sales revenue x 1.085 (100% + 8.5%) = 78120

sales revenue = 78120/1.085

sales revenue = 72000

total sales including tax - sales revenue = sales tax

78120 = 72000 = 6120

Journal entry:

cash.      78120

  Sales revenue.     72000

  Sales tax payable.  6120

The length of a rectangle is 2 cm less than twice the width. The area of the rectangle is 112 cm2. Find the length and width of the rectangle.

Answers

Let breadth be x

Length=2x-2

We know

[tex]\boxed{\sf Area=Length\times Breadth}[/tex]

[tex]\\ \sf\longmapsto 112=x(2x-2)[/tex]

[tex]\\ \sf\longmapsto 2x^2-2x-112=0[/tex]

[tex]\\ \sf\longmapsto x=-7\:or\:x=8[/tex]

Ignore negative value

Now

[tex]\\ \sf\longmapsto Length=2x-2=2(8)-2=16-2=14[/tex]

[tex]\\ \sf\longmapsto Breadth=8[/tex]

What is the y value when x is -5? What about 5?

I’ve done all three functions and the answers are -9, 24 and -4 but I don’t know which one to answer as the y value with. Please help.

Answers

-5 is between -2 and -10 So you use that problem
-20 + 11 = -9

When you use 5. It is between 2 and 10. So you use that problem
5+ 1 = 6

Find x (round to the nearest tenth)

Answers

9514 1404 393

Answer:

  x = 8

Step-by-step explanation:

By AA similarity, ΔABD ~ ΔCDE. So, corresponding sides are proportional.

  AB/BD = CD/DE

  x/12 = 4/6

  x = 12(4/6)

  x = 8

Point g is located at (3,6) on the coordinate plane. Point G is reflected over the x-axis to create point G'. Point G' is then reflected over the y-axis to create point G''. What ordered pair describes the location of G''.

Answers

-Answer:

(-3. -6)

Step-by-step explanation:

G (3,6)

x axis reflect

G' (3, -6)

y axis reflect

G'' (-3. -6)

I need help with the questions that are blank

Answers

9514 1404 393

Answer:

  TRIANGLES

  Possible

     4) Yes

  Unique

     1) No

     2) No

     3) Yes

  3D SHAPES

     Step 2: triangle area 8.75 ft²; total area 52.5 ft²

     Step 3: TOTAL AREA = 52.5 ft² + 31.5 ft² = 84 ft²

Step-by-step explanation:

TRIANGLES

Possible Triangles

The requirement on side lengths is that the sum of the short two exceed the longest.

  4) 5 + 6 = 11 > 7 . . . . Yes, can form a triangle

__

Unique Triangles

The available congruence theorems are a good starting point for determining if a triangle is unique. If you have side and angle definitions that correspond to AAS, ASA, SAS, SSS, or HL, then the triangle is uniquely determined.

You will notice that SSA is not on this list. However, there are special cases where SSA can be used. If the given angle is opposite the longest given side, then the triangle is uniquely determined. (You will notice that this is the case in an HL triangle, where the given H side is opposite the right angle.)

  1) SSA; angle is opposite the short side — triangle is not unique

  2) AAA; no side is given — triangle is not unique

  3) SAS; — triangle is unique

__

3D SHAPES

  Step 2: The area is 1/2bh = 1/2(3.5 ft)(5 ft) = 8.75 ft². The area of all triangles together is 6×8.75 ft² = 52.5 ft².

  Step 3: TOTAL AREA = 52.5 ft² + 31.5 ft² = 84 ft².

PLEASE HELP

Solve the equation for y. Identify the slope and y-intercept then graph the equation.

Y=-3x+1

Y=
M=
B=

Please Include a picture of the graph and show your work if you can

Answers

The equation is already solved for y

It's in y = mx+b form where

m = -3 = slope

b = 1 = y intercept

The graph is shown below. It's a straight line through the two points (0,1) and (1,-2).

Note that (0,1) is the y intercept. We use the slope = -3 = -3/1 to move 3 units down and 1 unit to the right to arrive at (1,-2).

Find the sum of the first 274 natural numbers.

Answers

Answer:

37675

Step-by-step explanation:

ummm what is did was

274/2 = 137

and then times that by 275

because

274+1 = 275

273+2 = 275

...

137+137 = 275

so the ans is 137(275) which is equal to 37675

Select the line segment.
O A.
P
OB.
R
S
Ос.
M
N
OD.
G
H

Answers

Answer: Choice A

Explanation: A segment (or line segment) is whenever we have two endpoints connected with a straight line. It does not go on forever in either direction.

Answer:

Step-by-step explanation:

B is a ray. One of its ends is stationary.

C is an arc which means it bends

D is a line.

That means that A is the answer. Both its ends are stationary.




Kevin baked 44 cookies. His family ate d of them. Using d, write an expression for the number of cookies that remained

Answers

Answer:

44-d

Step-by-step explanation:

Take the total number of cookies and subtract the number eaten.  That is the number remaining

44-d

Help me out!! Anyone

Answers

Answer:

4:10

Step-by-step explanation:

if they have to wait for plane B and it arrives every 10 mins then 4:10 is the anser

(a − 1/a)^2 − (a + 1/a)^2 =

(A) 4
(B) -4
(C) 2
(D) -2
(E) 2a

Answers

Answer:

(B) -4

Step-by-step explanation:

so, do the multiplications and see :

(a - 1/a)² = a² - 2×a/a + 1/a² = a² - 2 + 1/a²

(a + 1/a)² = a² + 2×a/a + 1/a² = a² + 2 + 1/a²

now we need to subtract the second from the first :

(a² - 2 + 1/a²) - (a² + 2 + 1/a²) =

= a² - 2 + 1/a² - a² - 2 - 1/a² = -4

and that's it !

.........................................................

Answers

Answer:

..............................what this

Find the inequality represented by the graph.

Answers

9514 1404 393

Answer:

  y < 3x -4

Step-by-step explanation:

The boundary line has a slope (rise/run) of 3/1 = 3. It has a y-intercept of -4. The shaded area is below the line and the solution does not include the line. The relevant inequality can be written ...

  y < 3x -4

A study was performed to determine the percentage of people who wear life vests while out on the water. A researcher believed that the percentage was different for those who rode jet skis compared to those who were in boats. Out of 400 randomly selected people who rode a jet ski, 86.5% wore life vests. Out of 250 randomly selected boaters, 92.8% wore life vests. Using a 0.10 level of significance, test the claim that the proportion of people who wear life vests while riding a jet ski is not the same as the proportion of people who wear life vests while riding in a boat. Let jet skiers be Population 1 and let boaters be Population 2.
Step 2 of 3:
Step 1 of 3:
State the null and alternative hypotheses for the test. Fill in the blank below.
H0Ha: p1=p2: p1⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯p2H0: p1=p2Ha: p1_p2
Step 3 of 3:
Draw a conclusion and interpret the decision.
Compute the value of the test statistic. Round your answer to two decimal places.

Answers

From the test the person wants, and the sample data, we build the test hypothesis, find the test statistic,  and use this to reach a conclusion.

This is a two-sample test, thus, it is needed to understand the central limit theorem and subtraction of normal variables.

Doing this:

The null hypothesis is [tex]H_0: p_1 - p_2 = 0 \rightarrow p_1 = p_2[/tex]The alternative hypothesis is [tex]H_1: p_1 - p_2 \neq 0 \rightarrow p_1 \neq p_2[/tex]The value of the test statistic is z = -2.67.The p-value of the test is 0.0076 < 0.05(standard significance level), which means that there is enough evidence to conclude that the proportion of people who wear life vests while riding a jet ski is not the same as the proportion of people who wear life vests while riding in a boat.

-------------------

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

-------------------------------------

Proportion 1: Jet-ski users

86.5% out of 400, thus:

[tex]p_1 = 0.865[/tex]

[tex]s_1 = \sqrt{\frac{0.865*0.135}{400}} = 0.0171[/tex]

Proportion 2: boaters

92.8% out of 250, so:

[tex]p_2 = 0.928[/tex]

[tex]s_2 = \sqrt{\frac{0.928*0.072}{250}} = 0.0163[/tex]

------------------------------------------------

Hypothesis:

Test the claim that the proportion of people who wear life vests while riding a jet ski is not the same as the proportion of people who wear life vests while riding in a boat.

At the null hypothesis, it is tested that the proportions are the same, that is, the subtraction is 0. So

[tex]H_0: p_1 - p_2 = 0 \rightarrow p_1 = p_2[/tex]

At the alternative hypothesis, it is tested that the proportions are different, that is, the subtraction is different of 0. So

[tex]H_1: p_1 - p_2 \neq 0 \rightarrow p_1 \neq p_2[/tex]

------------------------------------------------------

Test statistic:

The test statistic is:

[tex]z = \frac{X - \mu}{s}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, and s is the standard error.

0 is tested at the null hypothesis.

This means that [tex]\mu = 0[/tex]

From the samples:

[tex]X = p_1 - p_2 = 0.865 - 0.928 = -0.063[/tex]

[tex]s = \sqrt{s_1^2 + s_2^2} = \sqrt{0.0171^2 + 0.0163^2} = 0.0236[/tex]

The value of the test statistic is:

[tex]z = \frac{X - \mu}{s}[/tex]

[tex]z = \frac{-0.063 - 0}{0.0236}[/tex]

[tex]z = -2.67[/tex]

The value of the test statistic is z = -2.67.

---------------------------------------------

p-value of the test and decision:

The p-value of the test is the probability that the proportion differs by at at least 0.063, which is P(|z| > 2.67), given by 2 multiplied by the p-value of z = -2.67.

Looking at the z-table, z = -2.67 has a p-value of 0.0038.

2*0.0038 = 0.0076.

The p-value of the test is 0.0076 < 0.05(standard significance level), which means that there is enough evidence to conclude that the proportion of people who wear life vests while riding a jet ski is not the same as the proportion of people who wear life vests while riding in a boat.

A similar question is found at https://brainly.com/question/24250158

I think of number I add 14 to the number and multiply the result by 3 if my final answer is 51 what number did I think of​

Answers

Answer:

-1

Explanation:

Let the number be x.

Then the equation will be:

3(x+18) = 51

=> 3x + 54 = 51

=> 3x = 51 - 54

=> 3x = -3

=> x = -3/3

=> x = -1

So, the number you thought of is -1.

Answer:

The number is 3.

Step-by-step explanation:

[tex]3(14+x)=51\\42+3x=51\\3x=9\\x=3[/tex]

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