several psychology students are unprepared for a surprise​ true/false test with ​questions, and all of their answers are guesses. a. find the mean and standard deviation for the number of correct answers for such students. b. would it be unusual for a student to pass by guessing​ (which requires getting at least correct​ answers)? why or why​ not?

Answers

Answer 1

The mean and standard deviation for the number of correct answers for such students is; μ = 6.5 and σ = 1.802776

How to find the mean and standard deviation?

Given there is a surprise​ true/false test with 13​ questions.

Thus, the probability of correctly guessing the answer is; p=0.5

Let "X' be the answers correctly guess by a student.

The formula for the binomial probability distribution is;

P(X = x) = nCx * p^(x) * (1 - p)^(n - x)

A) The mean of the binomial distribution is given by the formula;

μ = np

μ = 13 * 0.5

μ = 6.5

The formula for standard deviation is:

σ = √(np(1 - p))

σ = √(13 * 0.5(1 - 0.5))

σ = 1.802776

B) The probability that the student getting at least 11 correct​answers is given by:

P(X ≥ 11) = P(X = 11) + P(X = 12) + P(X = 13)

Using online binomial probability calculator, we have;

P(X ≥ 11) = 0.01123

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Complete question is;

Several psychology students are unprepared for a surprise​true/false test with 13 ​questions, and all of their answers are guesses.

a. Find the mean and standard deviation for the number of correct answers for such students.

b. Would it be unusual for a student to pass by guessing​ (which requires getting at least 11 correct​ answers)? Why or why​not?


Related Questions

what does x have to measure to make the lines parallel?

PLEASE HELP ASAP

Answers

Answer:

23) 30°

24) 12°

Step-by-step explanation:

23) Lines will be parallel if the co interior angles are supplementary.

               ∠3 + ∠5 = 180°

 3x+ 25 + 4x - 55 = 180

3x + 4x + 25 -55 = 180

Combine like terms,

            7x -  30    = 180

Add 30 to both sides,

                7x = 180 + 30

               7x = 210

Divide both sides by 7,

                x = 210 ÷ 7

                x = 30

24)    If the lines are parallel, then the alternate interior angles are congruent.

                  ∠7 = ∠2

           11x - 36 = 8x

Add 36 to both sides,

                 11x   = 8x + 36

Subtract 8x from both sides,

          11x - 8x  = 36

                  3x = 36

                    x = 36 ÷ 3

x = 12°

Can someone please help i will give brainliest

Answers

The given function g(x) is positive for all real values of x, and increasing for the interval (-3,∞) , decreasing for the interval (-∞,-3) and

the end behavior is that g(x) → ∞ as x → -∞  an g(x) → ∞ as x → ∞ .

In the question ,

the graph of the function g(x) is shown  ,

we see that ,No part of the graph of function g(x) is below the x axis ,

So, the negative of the function g(x) does not exist .

Also from the graph we can see that the graph is above the x axis for all values of x,

So , the function g(x) is positive for all real values of x .

the graph shows that the function is decreasing for x<-3 means

function g(x) is decreasing in the interval (-∞,-3) .

the graph shows that the function is increasing for x>-3 means

function g(x) is increasing in the interval (-3,∞) .

From the graph ,

the end behavior of the function g(x) is that g(x) → ∞ as x → -∞   and g(x) → ∞ as x → ∞

Therefore , the given function g(x) is positive for all real values , and increasing for the interval (-3,∞) , decreasing for the interval (-∞,-3) and

the end behavior is that g(x) → ∞ as x → -∞   and g(x) → ∞ as x → ∞ .

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If I have 22,590$ and I need to get to 52,900$ how much money do I need.

Answers

Answer:

30310$

Step-by-step explanation:

1/3 of a number is added to 5. The result is one and a half times the original number​

Answers

Answer:

let the number be x...therefore 1/3 of x equals to 1/3x

1/3x+5=6/5x....collect like terms

1/3x-6/5x=-5

0.3x - 1.2x = -5

-0.9x = -5

Divide both sides by coefficient of x....

X = -5/-0.9

=5.55

=5.6

Suppose 54 gallons of water came out of a pipe in 9 minutes. What was the rate in gallons per minute?

Answers

Answer:

6 gallons per minute

Step-by-step explanation:

54 gallons came out in 9 minutes

54/9 = 6

the rate is 6 gallons per minute

Stuck with this question, I hope it goes right but I put in 15 points so

Have a good day and thanks in advance to anyone who helps me.

Answers

Jake has 1/2 yards left of cloth

Which number line represents the solution set for the inequality 3(8 – 4x) < 6(x – 5)?

A number line from negative 5 to 5 in increments of 1. An open circle is at 3 and a bold line starts at 3 and is pointing to the left.
A number line from negative 5 to 5 in increments of 1. An open circle is at 3 and a bold line starts at 3 and is pointing to the right.
A number line from negative 5 to 5 in increments of 1. An open circle is at negative 3 and a bold line starts at negative 3 and is pointing to the left.
A number line from negative 5 to 5 in increments of 1. An open circle is at negative 3 and a bold line starts at negative 3 and is pointing to the right.

Answers

The solution of the inequality will be;

⇒ A number line from negative 5 to 5 in increments of 1. An open circle is at 3 and a bold line starts at 3 and is pointing to the right.

What is Inequality?

A relation by which we can compare two or more mathematical expression is called an inequality.

Given that;

The expression for the inequality will be;

⇒ 3(8 – 4x) < 6(x – 5)

Now, Solve the inequality as;

The expression for the inequality will be;

= 3(8 – 4x) < 6(x – 5)

Divide by 3 both side,

= 8 - 4x < 2 (x - 5)

= 8 - 4x < 2x - 10

Add 4x both side;

= 8 - 4x + 4x < 2x - 10 + 4x

= 8 < 6x - 10

Add 10 both side;

= 18 < 6x

Divide 6 both side;

= 3 < x

So, The solution of the inequality will be;

⇒ A number line from negative 5 to 5 in increments of 1. An open circle is at 3 and a bold line starts at 3 and is pointing to the right.

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FIRST PERSON TO ANSWER GETS BRAINLIEST
2. Melanie’s bank account balance is. She needs to pay $55 to her cell phone carrier and $80 to the landscaper. She also expects $250 from her sister to be added to her account.

(a) Write an expression Melanie can use to determine her bank account balance after paying these bills and receiving money from her sister.
(b) What is Melanie’s bank account balance after paying her bills and receiving money? Show any necessary work. Answer in a complete sentence

Answers

Answer:

Describe how anthropology challenges more commonly held notions of progress

Step-by-step explanation:

Write the equation of a line that has a slope of 1/2 and a y-intercept of (0,-4) in standard form.
Write the equation that contains the point (-5,2) and in which the slope equals 1/2 in standard form.
Write the equation of the line in which the x-intercept is 2 and the y-intercept is 8 in slope-intercept form.

Answers

Considering the definition of a line, you get:

the equation of a line that has a slope of 1/2 and a y-intercept of (0,-4) is y= 1/2x -4.the equation that contains the point (-5,2) and in which the slope equals 1/2 is is y= 1/2x +9/2.the equation of the line in which the x-intercept is 2 and the y-intercept is 8 is y=-4x +8.

Linear equation

A linear equation o line can be expressed in the form y = mx + b

where

x and y are coordinates of a point.m is the slope.b is the ordinate to the origin and represents the coordinate of the point where the line crosses the y axis.

Equation of a line that has a slope of 1/2 and a y-intercept of (0,-4)

In this case, you know:

The line has a slope of 1/2.The line passes through the point (0, -4).

Substituting the value of the slope m and the value of the point in the expression of a linear equation, y = mx + b, the value of the ordinate to the origin b can be obtained:

-4= 1/2×0 + b

-4= 0 + b

-4 = b

Finally, the equation of the line is y= 1/2x -4.

Equation that contains the point (-5,2) and in which the slope equals 1/2

In this case, you know:

The line has a slope of 1/2.The line passes through the point (-5, 2).

Substituting the value of the slope m and the value of the point in the expression of a linear equation, y = mx + b, the value of the ordinate to the origin b can be obtained:

2= 1/2×(-5) + b

2= -5/2 + b

2 + 5/2= b

9/2 = b

Finally, the equation of the line is y= 1/2x +9/2.

Equation of the line in which the x-intercept is 2 and the y-intercept is 8

Knowing two points (x₁, y₁) and (x₂, y₂) of a line, the slope m of said line can be calculated using the following expression:

m= (y₂ - y₁)÷ (x₂ - x₁)

Substituting the value of the slope m and the value of one of the points in the expression of a linear equation, y = mx + b, the value of the ordinate to the origin b can be obtained.

Being (x₁, y₁)= (2,0) [x-intercept] and (x₂, y₂)= (0,8) [y-intercept] , the slope m can be calculated as:

m= (y₂ - y₁)÷ (x₂ - x₁)

m= (8- 0)÷ (0 -2)

m= 8÷ (-2)

m= -4

Considering point 2 and the slope m, you obtain:

8= -4×0 + b

8= 0 +b

8=b

Finally, the equation of the line  y=-4x + 8.

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3y+1=6x in y intercept form.

Answers

Answer:-1/3

Step-by-step explanation:

3y+1=6x

Minus 1 on both side so,

3y=6x-1

Then divide 3 on both side so,

y=2x-1/3

The number behind x is y intercept which -1/3 and the - sign have to be inside.

For
f(x)= −3x5+1, f(–10)=7
7 is the answer but i dont have the work

Answers

Answer:

f(-10) = -299999

Step-by-step explanation:

Equation

f(x)= −3x^55+1

Given

x = - 10

Solution

You have to understand what f(x) means. When you put a value in for x, every x on the right is supplied with that value.

In this case I take the equation to mean what ever we are given in the brackets (in this case 10) is what goes into the x on the right. So the new equation is

f(-10) = -3*(-10)^5 + 1

(- 10) ^5 = - 100000

f(-10) = -300000 + 1

f(-10) = -299999

What do you know to be true about the values of a and b?

A. a B. a = b
C. a>b
D. Can't be determined

Answers

Option A is the correct Answer a<b.

How to find the angle of triangles?

From the figure, we can see both are  isosceles triangles.From the first figure we can calculate the

                angle a= 180-(75+75)=30°

the second figure shows the angle b =60°

         to confirm that a<b.

An isosceles triangle has two equal sides as well as two equal angles. The Greek words iso (same) and skelos are the source of the name (leg). An equilateral triangle is one in which all of its sides are equal, whereas a scalene triangle is one in which none of its sides are equal.If either of a triangle's two sides is equal, the triangle is said to be isosceles. Let's consider a triangle with the sides AB, BC, and CA. The triangle is isosceles if any of these statements—AB = BC, BC = CA, or CA = AB—are accurate.

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HELPPPPP #STRESSEDTHEHECKOUT

Answers

Answer:

Ok so first change the fractions to decimals and the top one is five

what is (1/6-0.5). divided by 5/11

Answers

Answer: I think the answer is -11/15

Step-by-step explanation:[tex]\frac{1}{6}[/tex]-0.5   0.5=[tex]\frac{1}{2}[/tex]

                                           [tex]-\frac{1}{3}[/tex] divided by [tex]\frac{5}{11}[/tex] = [tex]\frac{11}{15}[/tex]


5. A rocket is launched from atop a 68-foot cliff with an initial velocity of 139 feet per
second. The height of the rocket t seconds after launch is given by the equation
h=-16t² + 139t+ 68. How long after the rocket is launched will it be 12 feet from the
ground? Round to the nearest hundredth of a second.

Answers

Answer: Its t=

32

23673−64h

+139

Step-by-step explanation:

Solve the equation. If there is no solution, write no
solution (still show work).
| + 2| = 4

Answers

Answer: no solution

Step-by-step explanation:

Lisa's family is planning a trip to Orlando, Florida which is 645 miles away from their
home. If Lisa's family travels 65 miles per hour, at least how many hours will it take
them to get to Orlando?

Answers

Answer:

about 9.92 hours (at least 9 hours, almost 10 hours)

Step-by-step explanation:

645 miles / 65 mph = about 9.92 hours

?:12 =7:14 what is the answer

Answers

6 is the answer because 14 divided by 2 =7
12 divided by 2 = 6

Part A Write the multiplication expression shown by the model. Do not solve the problem.
help​

Answers

The multiplication expressions shown by the model are:

Green squares: (4 x 10) + (1 x 6)Red squares: (4 + 2) + (4 x 10)Blue squares: (8 x 2) (3 x 10)Ash squares: (2 + (6 x 10)

What are multiplication expressions?

A multiplication expression is a mathematical statement that uses the multiplication operand with either number, variables, or a combination of the two to produce results.

The numbers or variables in a multiplication expression are known as multiplicand (the first number to be multiplied) and multiplier (the second number multiplying).

The result or solution of a multiplication operation is known as the product.

Thus, other possible multiplication expressions can be written out from the model because of the additive property of multiplication.

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On Monday, a local hamburger shop sold a combined total of 416 hamburgers and cheeseburgers. The number of cheeseburgers sold was three times the number of hamburgers sold. How many hamburgers were sold on Monday?
(Will mark brainliest plus 100 points)

Answers

A nearby hamburger joint sold 416 hamburgers and cheeseburgers in total on Monday. 104 hamburgers were sold.

Given that,

A nearby hamburger joint sold 416 hamburgers and cheeseburgers in total on Monday. Three times as many cheeseburgers were sold as regular hamburgers.

We have to find on Monday, how many hamburgers were sold.

Let us take hamburgers were sold as h and cheeseburgers were sold as c.

Quantity equation is h+c=416

c=3h

Substitute c =3h in h+c=416

h+3h=416

4h=416

h=104

Now,

Substitute h=104 in c=3h

c=3×104

c=312

Therefore, 104 hamburgers were sold.

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Henry is buying school supplies for the start of the school year for every 3 pencils he buys 2 pens if Henry buys 21 pencils how many total pencils and pens did Henry buy​

Answers

Total number of pencils and pens bought by Henry = 35.

What is the unitary method of problem solving?
The unitary technique, in its most basic form, is used to calculate the value of a single unit from a specified multiple. The unitary approach can be used to complete it. Additionally, after determining the value of a single unit, we can multiply that value by the number of units needed to determine the value of the additional units. The concept of ratio and proportion is mostly applied using this way.

Given, for every 3 pencils, number of pens bought = 2
Therefore, every 1 pencil, number of pens bought = 2/3
Thus, for 21 pencils, number of pens bought = (2/3)*21 = 14
Therefore, total number of pencils and pens bought by Henry = 21 + 14 = 35.

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Which is the following numbers is the closest to six
38
34
33
37?

Answers

33???????????like to the number 6? Its the least one then ig lol

Kindly help and mention which one youve solved

Answers

The value of  m²+n²+p² is 46.

What is algebraic identities?

In mathematics, an identical element, also known as a neutral element, is an element of a set that, when subjected to a binary operation, leaves each element of the set intact. In algebraic structures like groups and rings, this idea is applied. Algebraic identities are algebraic equations that are true regardless of the value of each variable. Additionally, they are employed in the factorization of polynomials. Algebraic identities are employed in this manner for the computation of algebraic expressions and the solution of various polynomials.

Given Data

m + n+ p= 10

mn + np + mp = 27

For m² + n²+ p²

Using algebraic identities,

(m+ n +p)² = m² + n² + p² +2(mn + np + pm)

(10)² = m² +n² + p² + 2(27)

100 = m² + n² + p² + 54

100 - 54 = m² + n² + p²

46 = m²+n²+p²

The value of  m²+n²+p² is 46.

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two coins are tossed. the probability of at least getting one head is ?

Answers

Answer:1/2

Step-by-step explanation:

2 heads

2 tails

2 + 2 = 4

heads - 2/4 - total

1/2

It's Joey's 8th birthday! Joey's favorite present is the 8 baseball cards that he got from his dad. Joey has never owned a baseball card before this gift, and he decides that he wants to start collecting baseball cards.

He plans to collect 3 baseball cards each month until he has a total of 50 cards.

Let x represent the number of months Joey collects the baseball cards.

Which equation can Joey use to determine how many months it will take to reach his goal?

Answers

The equation that Joey can use to determine how many months it will take to reach his goal will be 8 + 3x = 50 and the number of months is 14.

How to illustrate the information?

From the information, Joey's favorite present is the 8 baseball cards that he got from his dad and he has never owned a baseball card before this gift and he plans to collect 3 baseball cards each month until he has a total of 50 cards.

This will be illustrated as:

8 + 3x = 50

Collect like terms

3x = 50 - 8

3x = 42

Divide through 3

3x / 3 = 42 / 3

x = 14

The number of months is 14.

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3. Triangle JKL is shown below. Which of the following is not a true statement about the angles in the triangle? A. The sum of 2J + 2K+ ZL = 180°. B. The measure of ZJ is 65°. C. The measure of ZK is 89°. D. The measure of ZL is 43°. 7x+2 J K 8x 7x + 2 4x + 7 L​

Answers

The statement that is not true about the angles in the triangle is OPTION C. The measure of ∠K is 89°

What is an equation?

An equation is an expression that shows the relationship between two or more numbers and variables.

Equations are classified based on degree (value of highest exponents) as linear, quadratic, cubic and so on. Variables can be dependent or independent. Dependent variables depend on other variable while an independent variable do not depend.

From the diagram:

∠J + ∠K + ∠L = 180° (angles in a triangle)

Substituting:

(7x + 2) + (8x) + (4x + 7) = 180

19x + 9 = 180

x = 9

∠J = 7x + 2 = 7(9) + 2 = 65°

∠K = 8x = 8(9) = 72°

∠L = 4x + 7 = 4(9) + 7 = 43°

∠k ≠ 89°

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A group of friends take a tubing trip the company charges $15 for a regular tube and $7.50 for a cooler tube. Together they spent $360 to rent. How many of each tube did they rent?

Answers

The no. of regular tube costing $15 were 12 and the cooler tube costing $7.5 each were 24

What is a tubing?

The entire family can participate in tubing. Change into swimwear, rent a tube and a life jacket, and float down the river—that it's easy. Numerous outfitters provide transportation to the best waterways and rent tubes from Blue Ridge to Columbus, via Helen and Columbus.

The total cost of rent on tube = $360

Price of regular tube = $15

Price of cooler tubes = $7.5

Let the no. of regular tubes be and cooler tubes be y

The equation forms

15x + 7.5y = 360           ...1

As we can notice regular tube is twice the price of cooler tubes, sthe the equation forms

2(7.5) = 15

This means when y = 2, x = 1

cross multiply them and we find

2/y = 1/x

x/y = 1/2

x = y/2               ...2

Putting the value of x in eq 1, we get

15(y)/2 + 7.5y = 360

7.5y + 7.5y = 370

15y = 360

y = 360/15

y = 24

Putting the value of y in eq 1, we get

15x + 7.5(24) = 360

15x + 180 = 360

15x = 360 - 180

15x = 180

x = 180/15

x = 12

Thus, The no. of regular tube costing $15 were 12 and the cooler tube costing $7.5 each were 24.

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What is the distance between (3,-4) and (5,6)

Answers

Answer:

Step-by-step explanation:

eedrfgrtrf3re3

ANSWER:

(3,-4)= -2  (5,6)= -10 and if you need to divide it would be 0.2

Step-by-step explanation:

What I did was get the y- axis number with each other and minus them so that would be (3, - 5) = -2 and then I did (-4 - 6)= -10 and then you can divided -2/-10= 0.2. Hope this helped!

PLSSS I NEED HELP ASAP

Answers

Answer:

19. x=20 y=7 20. x=10 y=25 21. x=12 y=31

Step-by-step explanation:

worksapce thingy

3x+17=5x-7

2x=24 x=12

53

no idea if im right .-.

rereciporical of 1/2

Answers

Answer: 2 or 2/1

Step-by-step explanation: the reciprocal of 1/2 is 2/1. in decimal form, 2 is the reciprocal of 0.5.

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