Signed numbers are also called directed numbers true or false

a) The percent of the scores are between 72 and 87 is 77.45%

b) The probability that a score is greater than 77 is 84.13%

c) The probability that a score is less than 82 or greater than 92 is 52.28%

d) About 5 students scored outside two standard deviations of the mean.

a) To find the percent of scores between 72 and 87, we first need to standardize these scores. We can do this by subtracting the mean (82) and dividing by the standard deviation (5). This gives us:

z = (72 - 82) / 5 = -2

z = (87 - 82) / 5 = 1

We can then use a table of standard normal probabilities (also called a z-table) to find the probability of a score being between -2 and 1. This probability is 0.7745, or 77.45%

b) To find the probability that a score is greater than 77, we again need to standardize the score:

z = (77 - 82) / 5 = -1

Using the z-table, we can find the probability of a score being greater than -1 (which is the same as the probability of a score being less than or equal to 77). This probability is 0.1587, or 15.87% (rounded to two decimal places). To find the probability of a score being greater than 77, we subtract this probability from 1:

P(score > 77) = 1 - P(score <= 77) = 1 - 0.1587 = 0.8413, or 84.13%

c) To find the probability that a score is less than 82 or greater than 92, we can break this into two separate probabilities:

P(score < 82) + P(score > 92)

We can standardize these scores as follows:

z = (82 - 82) / 5 = 0

z = (92 - 82) / 5 = 2

Using the z-table, we can find the probabilities associated with these z-scores:

P(score < 82) = P(z < 0) = 0.5 (from the symmetry of the standard normal distribution)

P(score > 92) = P(z > 2) = 0.0228

Adding these probabilities together gives us:

P(score < 82 or score > 92) = 0.5 + 0.0228 = 0.5228, or 52.28%

d) Two standard deviations from the mean in either direction would be:

82 - (2 x 5) = 72

82 + (2 x 5) = 92

So any score below 72 or above 92 would be considered outside two standard deviations. To find how many students scored outside this range, we need to find the total proportion of scores that fall outside this range and multiply by the total number of scores.

To find the proportion of scores outside the range, we can use the same approach as in part c):

P(score < 72 or score > 92) = P(z < -2 or z > 2) = P(z < -2) + P(z > 2)

Using the z-table, we find:

P(z < -2) = 0.0228

P(z > 2) = 0.0228

Adding these probabilities together gives us:

P(score < 72 or score > 92) = 0.0228 + 0.0228 = 0.0456

So 4.56% of scores fall outside the range of 72 to 92. To find the number of students who scored outside this range, we can multiply this proportion by the total number of scores:

0.0456 x 120 = 5.472 ≈ 5

To know more about probability here

https://brainly.com/question/11234923

#SPJ1

Answer:

not sure sorry -(1,0)and (2,0)

The polynomial 18x^3 + 6x^2y - 9x^2 - 3xy when factored completely is (6x^2 - 3x)(3x + y)

From the question, we have the following parameters that can be used in our computation:

18x^3 + 6x^2y - 9x^2 - 3xy

Factoize the expression

So, we have

6x^2(3x + y) - 3x(3x + y)

Factor out 3x + y

So, we have

(6x^2 - 3x)(3x + y)

Hence, the solution is (6x^2 - 3x)(3x + y)

Read more about expression at

https://brainly.com/question/15775046

#SPJ1

The exact value of x  in the right triangle is 3√10

From the question, we have the following parameters that can be used in our computation:

Similar triangles

Using the theorem of corresponding sides in similar triangles, we have

x/15 = 6/x

When both sides of the equation are cross multplied, we have

x^2 = 90

Take the square root of both sides

So, we have

x = 3√10

Hence, the exact value of x is 3√10

Read more about right triangle at

https://brainly.com/question/2437195

#SPJ1

The requreid Mona's phone call was 13 minutes long.

Let's let the variable "m" represent the length of the phone call in minutes.

We know that Mona pays $1.00 for the first call of the day plus $0.15 per minute of the call. So the total cost of the call can be represented by the expression:

$1.00 + $0.15m

We also know that Mona paid $2.95 for her first call today. So we can set the expression for the total cost of the call equal to $2.95:

$1.00 + $0.15m = $2.95

To solve for the length of the call in minutes, we can first subtract $1.00 from both sides of the equation:

$0.15m = $1.95

Then we can divide both sides by $0.15:

m = 13

Therefore, Mona's phone call was 13 minutes long.

Learn more about expression here:

https://brainly.com/question/14083225

#SPJ1

11.2% of the mass of a water molecule is hydrogen

As water is composed of two parts hydrogen and one part oxygen, the total mass of a single molecule may be determined by ascertaining the following:

The Total Mass of Water = (2 x Mass of Hydrogen) + (1 x Mass of Oxygen)

Total Mass of Water = (2 x 1.01u) + (1 x 16.00u)

Total Mass of Water = 18.02u

Consequently, the overall mass of one molecule of water is determined to be 18.02 atomic mass units (u).

% mass of hydrogen = (mass of hydrogen / total mass of water) × 100

% mass of hydrogen = (2.02u / 18.02u) × 100

% mass of hydrogen = 11.2%

Read more on oxygen and hydrogen here: https://brainly.com/question/2111051

#SPJ1

Answer: The box goes from Q1 to Q3, with the middle spoken to by a line interior the box at Q2. The bristles expand from the box to the least and most extreme values. There's one exception, spoken to by an bullet (*), at the esteem of 90.

Step-by-step explanation: box and whisker plot:

|

90 ---| *

84 ---|

83 ---|

80 ---|_____

79 ---| |_____

| | |

76 ---| | |

| | |

72 ---|_____| |

71 ---| |

70 ---|___________|

66 75

The probability that both events occur is 0.06.

The probability that both events occur is calculated as follows;

P(A and B) = P(A) x P(B)

The probability of event A is;

P(A) = number of outcomes / total number of outcomes

P(A) = 2/6

P(A) = 1/3

The probability of event B is;

P(B) = number of outcomes / total number of outcomes

P(B) = 1/6

The probability of both events is;

P(A and B) = P(A) x P(B)

P(A and B) = (1/3) x (1/6)

P(A and B) = 1/18 = 0.06

Learn  more about probability here: https://brainly.com/question/24756209

#SPJ1

A) A probability of approximately 0.128 or 12.8% that exactly 17 students had type A blood.

B) There is a 93.0% chance that at least 17 students had type A blood in the blood drive held at University High.

Part A: To find the probability that exactly 17 of the 50 students had type A blood, we first need to calculate the probability of a single student having type A blood. Since about 31% of the U.S. population has type A blood, the probability of a student at University High having type A blood is also 31%.

We can use the binomial distribution formula to calculate the probability of exactly 17 students having type A blood in a sample of 50 students. The formula is:

P(X = x) = (n choose k) x pˣ x (1-p)ⁿ⁻ˣ

where P(X = x) is the probability of exactly x successes, n is the sample size (in this case, 50), p is the probability of success (31% or 0.31), (n choose k) is the binomial coefficient or the number of ways to choose k successes from n trials.

Plugging in the values, we get:

P(X = 17) = (50 choose 17) x 0.31¹⁷ x (1-0.31)⁵⁰⁻¹⁷ = 0.128 or 12.8%

Part B: To find the probability that at least 17 of the 50 students had type A blood, we need to calculate the probability of 17, 18, 19,...50 students having type A blood and then add those probabilities together. This is because "at least 17" means 17 or more students, so we need to consider all possibilities from 17 to 50.

Therefore, the probability of at least 17 students having type A blood is:

P(X >= 17) = 1 - P(X < 17)

where P(X < 17) is the probability of less than 17 students having type A blood. We can use the binomial distribution formula to calculate this probability as well:

P(X < 17) = P(X = 0) + P(X = 1) + ... + P(X = 16)

Again, this can be a tedious task to calculate manually. Instead, we can use a binomial calculator or a software program to find this probability.

Using a binomial, we find that the probability of less than 17 students having type A blood is approximately 0.070 or 7.0%. Therefore, the probability of at least 17 students having type A blood is:

P(X >= 17) = 1 - P(X < 17) = 1 - 0.070 = 0.930 or 93.0%

To know more about probability here

https://brainly.com/question/11234923

#SPJ4

Answer:Find the rational roots of x^4+5x^3+7x^2-3x-10=0

To find the rational roots of a polynomial, we use the Rational Root Theorem, which states that if a polynomial has rational roots, then they must be of the form p/q, where p is a factor of the constant term and q is a factor of the leading coefficient. In this case, the constant term is -10, and the leading coefficient is 1. The factors of 10 are ±1, ±2, ±5, and ±10, and the factors of 1 are ±1. Therefore, the possible rational roots are:

±1, ±2, ±5, ±10

We can test each of these roots by synthetic division or long division to see if they are actually roots of the polynomial. After trying these roots, we find that only -2 and 1 are roots. Therefore, the answer is A. -2,1.

Find all the zeros of the equation 3x^2-4=-x^4

We can rewrite the equation as x^4+3x^2-4=0. To find the zeros of this equation, we can use the Rational Root Theorem as in the previous question, except that now the factors of the constant term -4 are ±1, ±2, and ±4. The factors of the leading coefficient 1 are ±1. Therefore, the possible rational roots are:

±1, ±2, ±4

Testing these roots, we find that the only roots are x=1, x=-1, x=2i, and x=-2i. Therefore, the answer is D. 1,-1,2i,-2i.

What is a polynomial function in standard form with zeros 1,2,-2, and -3?

If a polynomial has roots a, b, c, and d, then it can be written as (x-a)(x-b)(x-c)(x-d). To put it in standard form, we need to expand this expression:

(x-a)(x-b)(x-c)(x-d) = x^4 - (a+b+c+d)x^3 + (ab+ac+ad+bc+bd+cd)x^2 - (abc+abd+acd+bcd)x + abcd

Substituting the given values of a, b, c, and d, we get:

(x-1)(x-2)(x+2)(x+3) = x^4 + 2x^3 - 7x^2 - 8x + 12

Therefore, the answer is B. x^4+2x^3-7x^2-8x+12.

Which correctly describes the roots of the following cubic equation.

x^3-3x^2+4x-12=0

We can use the Rational Root Theorem again to find the possible rational roots of the polynomial. The factors of the constant term -12 are ±1, ±2, ±3, ±4, ±6, and ±12, and the factors of the leading coefficient 1 are ±1. Therefore, the possible rational roots are:

±1, ±2, ±3, ±4, ±6, ±12

Testing these roots, we find that none of them are roots of the polynomial. Therefore, the answer is B. one real root and two complex roots.

What is the solution of 5^3x=900. Round your answer to the nearest hundredth

We can solve for x by taking the logarithm of both sides with base 5:

log5(

Step-by-step explanation:

The answers to all parts are shown below.

Equations are mathematical statements with two algebraic expressions flanking the equals (=) sign on either side.

Coefficients, variables, operators, constants, terms, expressions, and the equal to sign are some of the components of an equation. The "=" sign and terms on both sides must always be present when writing an equation.

1. x⁴ + 5x³ + 7x² -3x - 10 = 0

= (x-1)(x+2)(x² + 4x + 5)

Thus, the rational roots are 1 and -2.

2. 3x² -4 = - x⁴

x⁴ + 3x² -4 = 0

(x-1)(x+1)(x² + 4) =0

Thus, the zeroes are 1, -1, -2i, +2i.

3. We can write the zeroes as

p(x)=(x-1)(x-2)(x+2)(x+3).

So, p(x) = x⁴ + 2x³ -7x² -8x +12

4. x³ -3x² +4x- 12=0

(x-3)(x²+4) =0

x= 3, -2i, 3i

5.  x= 1,2,4,6,8,10,11

y= 0,-1,0,4,8,9,8

So, equation of line

(y- 0) = (-1-0)/(2-1)(x-1)

y = -1(x-1)

y + x +1=0

6. x= 2,5,12,20 and y= 30,12,5,3

k = 30/2

k = 15

So, the relationship is y= 15x.

7. cn = constant(k)

n= 44

then, c= 30/44 = 0.68

and, k = 44 x 0.68

k = 30

So, c = 1.5 dollars per person.

8. 125¹/³

= (5³)¹/³

= 5

9. y = 293(1.06)⁴ = 370

10. log₃ 2187

= log₃ 3⁷

= 7

11. log₄ 22

= 2.29

12 . y= 4/x

The new equation is  y = 4/(x - 7) + 6.

13. (6-x)/ (x² + 2x - 3) / (x² -4x- 12)/ (²x² + 4x + 3)

= - (x+1)/ (x+1)(x+2)

Learn more about Equation here:

https://brainly.com/question/29657983

#SPJ5

Answer:

4 minutes and 44 seconds.

The frequencies based on the information are are 100, 40, and 6.

In the formula of the median, we have to calculate cumulative frequencies and have to use cumulative frequency of the interval previous to the median class. Also, in the formula of mode, frequencies are used and not the cumulative frequencies.

140 - y = 100

y = 40

substituting y and x in equation 1 is:

x + y + z = 146

100 + 40 + z = 146

z = 6

Therefore, the missing frequencies are 100, 40, and 6.

Learn more about median on

https://brainly.com/question/26177250

#SPJ1

Answer:

v=-5

Step-by-step explanation:

Answer:

[tex]23 = 10v - 7 \\ 23 + 7 = 10v \\ 30 = 10v \\ v = 3 \\ \\ [/tex]

Answer:

Step-by-step explanation:

20.9 is solution

Yes, the table represents a proportional relationship.

The constant of proportionality is equal to 9.

In Mathematics and Geometry, a proportional relationship refers to a type of relationship that produces equivalent ratios and it can be modeled or represented by the following mathematical equation:

y = kx

Where:

Next, we would determine the constant of proportionality (k) by using the data points contained in the table as follows:

Constant of proportionality, k = y/x

Constant of proportionality, k = 18/2 = 45/5 = 63/7

Constant of proportionality, k = 9.

Read more on proportional relationship here: brainly.com/question/28350476

#SPJ1

Complete Question:

Tell whether each table represent a proportional relationship. If it does, identify the constant of proportionality.

1. X y 2 18 5 45 7 63​

The coordinates of the new point  is (-6, -2)

From the question, we have the following parameters that can be used in our computation:

Point = (6, 2)

Rule: 180 degrees rotation

The rule of 180 degrees rotation is

(x, y) = (-x -y)

substitute the known values in the above equation, so, we have the following representation

image = (-6, -2)

Hence, the image = (-6, -2)

Read more abotu transformation at

https://brainly.com/question/27224272

#SPJ1

The ratio to show the relationship is 13 : 12

From the question, we have the following parameters that can be used in our computation:

For every 13 white tiles used, she wants to use 12 gray tiles.

This means that

Ratio = White : Gray

Substitute the known values in the above equation, so, we have the following representation

Ratio = 13 : 12

Hence, the ratio of white tiles and the number of gray tiles is 13 : 12

Read more about ratio at

https://brainly.com/question/12024093

#SPJ1

Complete question

Demetria is tiling a square area of her bathroom floor. For every 13 white tiles used, 'she wants to use 12 gray tiles.

Write a ratio to show the relationship between the number of white tiles and the number of gray tiles.

Where the above factors are given, a sale price of approximately $84 for the immersion blenders will allow Kitchen Masters to achieve a profit of $89,300.

The profit equation for the sale of pressure cookers for the company Kitchen Masters is:

P = −120p² + 19,800p − 727,450

To find the sale price for the immersion blenders, p, that will allow Kitchen Masters to achieve a profit, P, of $89,300,


Let the profit equation =  89,300.

Now, we solve for p:

89,300 = −120p² + 19,800p − 727,450

Adding 727,450 to both sides:

816,750 = -120p² + 19,800p

Dividing both sides by -120:

-6,805 = p² - 165p

Rearrange the equation to make it Quadratic

p² - 165p + 6,805 = 0

Now we can solve for p using the quadratic formula:

p = (-b ± √(b² - 4ac)) / 2a

where a = 1, b = -165, and c = 6,805.

p = (-(-165) ± √((-165)² - 4(1)(6,805))) / 2(1)

p = (165 ± √((27,225 - 27220)) / 2

p ≈ 83.618 or p ≈ 81.382

Therefore, a sale price of approximately $84 for the immersion blenders will allow Kitchen Masters to achieve a profit of $89,300.

Learn more about profit equation :
https://brainly.com/question/15293328
#SPJ1

David has 15 dimes and 5 quarters.

Given that, David has twenty dimes (d) and quarters (q). These coins total $2.75.

Establishing the system of equations,

d + q = 20

d = 20 - q.............(i)

0.1d + 0.25q = 2.75..........(ii)

Put eq(i) in eq(ii),

0.1(20-q)+0.25q = 2.75

2-0.1q + 0.25q = 2.75

0.15q = 0.75

q = 5

Put q = 5 in eq(i)

d = 20-5

d = 15

Hence, David has 15 dimes and 5 quarters.

Learn more about system of equations, click;

https://brainly.com/question/12895249

#SPJ1

length, l=16in

width, b=13in

thickness, t=3in

To Find:-

Area of wrapping paper required.

Explanation:-

Since, wrapping paper is to be wrapped over the whole rectangular box.Therefore, we have to calculate the total surface area of the rectangular box.



Therefore, 590 of paper is required to wrap the whole rectangular box.

A graph represents a function if it has no vertically aligned points, that is, each value of x is mapped to only one value of y. Vertically aligned points mean that a value of x is mapped to multiple values of y, that is, a single input is mapped to multiple outputs which disqualify the relation as a function.

In this question, we have an horizontal line, meaning that it has a constant y-coordinate for each value of the y-input. Hence the graph represents a function.

For the domain and the range, we have that:

More can be learned about graphs and functions at https://brainly.com/question/12463448

#SPJ1

The calculated area of this triangle is 43.50 sq units

From the question, we have the following parameters that can be used in our computation:

The triangle

The area of the triangle is calculated as

Area = 1/2 * Product of adjacent legs * sin of middle angle

Substitute the known values in the above equation, so, we have the following representation

Area = 1/2 * 12 * 8 * sin(65)

Evaluate

Area = 43.50

Hence, the area is 43.50 sq units

Read more about area at

https://brainly.com/question/24487155

#SPJ1

The inequality is -8 < √74  < 9. A mathematical expression that's values on the left and right are not equal is referred to as having an inequality.

A mathematical expression that's values on the left and right are not equal is referred to as having an inequality. In essence, an inequality analyses any two values that demonstrates whether one is bigger than, less than, or neither greater nor equal to the other quantity. Numbers are compared using inequalities to determine a range of quantities that are contained inside the parameters of a variable.

Let A = √74

A² = 74

8² < A² < 9²

Hence, the inequality is -

8 < √74  < 9

To know more about inequality, here:

https://brainly.com/question/30231190

#SPJ1

The price of the motorcycle not including tax will be $12,000.

Given that:

Lenny bought a motorcycle. He paid 10.5% in tax.

The percentage is given as,

Percentage (P) = [Tax] / Initial value x 100

The price of the motorcycle not including tax is calculated as,

10.5 = (1260 / Initial value) x 100

0.105 = 1260 / Initial value

Initial value = 12,000

The price of the motorcycle is $12,000.

More about the percentage link is given below.

https://brainly.com/question/8011401

#SPJ1

The probability P (4)  and of getting more than 2 questions correct are 0.017 and 0.113 respectively.

The number of ways the student can answer each question is 4 (since there are 4 choices), so the probability of getting any one question correct by guessing is 1/4, and the probability of getting any one question wrong by guessing is 3/4.

We can use the binomial probability formula to find the probability of getting a specific number of questions correct out of the 10:

[tex]P(X = k) = ( ^kC _n) * p^k * (1-p)^(n-k)[/tex]

a) P(4) represents the probability of getting exactly 4 questions correct out of 10.

[tex]P(X = 4) = (^{10}C_4) * (1/4)^4 * (3/4)^{(10-4)} \approx 0.017[/tex]

So the probability of getting exactly 4 questions correct is approximately 0.017.

b) P(more than 2) represents the probability of getting 3, 4, 5, ..., or 10 questions correct out of 10. We can use the complement rule to find this probability:

P(more than 2) = 1 - P(X ≤ 2)

[tex]P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2)\\= (^{10} C_0) * (1/4)^0 * (3/4)^{10}+ (^{10} C_1) * (1/4)^1 * (3/4)^9+ (^{10} C_2) * (1/4)^2 * (3/4)^8\\\approx 0.887[/tex]

So,

P(more than 2) = 1 - P(X ≤ 2) ≈ 1 - 0.887 ≈ 0.113

Therefore, the probability of getting more than 2 questions correct is approximately 0.113.

Learn more about binomial probability here;

https://brainly.com/question/31197941

#SPJ1