The standard deviation of the sum of the 4 random variables is 10.23
The question is incomplete the complete question is
For each of the 4 stroke categories 2,4,6,8 consider a random variable representing the time of a randomly selected swimmer in that category is 0.6,0.8,0.2,0.7. What is the standard deviation of the sum of the 4 random variables?.
To calculate the Expected Value, we need to multiply each value by its probability and then sum the products up.
μ = E(x) = ∑xp(x)
That is, (0.6x2) + (0.8x4) + (0.2x6) + (0.7x8) = 1.2 + 3.2 + 1.2 + 5.6 = 11.2
Mean = 11.2
Now we take the first and second steps,
(2- 11.2)² x 0.6 = 84.64 x 0.6 = 50.78
(4 - 11.2)² x 0.8 = 51.84 x 0.8 = 41.47
(6 - 11.2)² x 0.2 = 27.04 x 0.2 = 5.4
(8 - 11.2)² x 0.7 = 10.24 x 0.7 = 7.16
Now we take the the third step and add our products together to get the variance V,
V = σ2 = ∑(x−μ)2P(x)
V = 50.78 + 41.47 + 5.4+ 7.16 = 104.81
Now we take the last step by taking the square root of the variance to get the standard deviation SD,
SD = σ = √σ2
Standard Deviation SD = √104.81 = 10.23
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OA. 20
B.O
345WN-OX
O C. -10
D. 10
0 -1
-2
-5
-10
-17
-26
-37
1
What is the average rate of change for this quadratic function for the interval
from x = 4 to x = 6?
2
6
Answer:
C. -10
Step-by-step explanation:
Using the average rate of change formula,
[tex]\frac{-37-(-17)}{6-4}=-10[/tex]
Draw a quadrilateral that has 2 separate pairs of equal length sides but is not a parallelogram.
A quadrilateral that has 2 separate pairs of equal length sides but is NOT a parallelogram is called a KITE.
What is a quadrilateral?
A quadrilateral is any polygon that has four sides and four vertices. They include;
Properties
Four sides (or edges)Four vertices (or corners), And internal angles that total 360 degrees make up a quadrilateral.What is a kite?
A quadrilateral is a polygon with four sides, commonly known as a kite. Four points on the plane must be "independent" in order for the kite to have four corners. As a result, none of the three are parallel to one another.
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the reflection of the point (8,0) across the x-axis is__
The reflection of the point (8,0) across the x-axis is (8, 0)
How to determine the image of the reflection?From the question, the point is given as:
Point = (8, 0)
Rewrite this point as
(x, y) = (8, 0)
The transformation is given as
Reflection across the x-axis
Mathematically, we have
(x, y) = (x, -y)
So,we have
Image = (8, 0)
Hence, the image of the reflection is (8, 0)
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A certain drug is made from only two ingredients: compound A and compound B. There are 5 milliliters of compound A used for every 6 milliliters of compound
B. If a chemist wants to make 671 milliliters of the drug, how many milliliters of compound A are needed?
If a chemist wants to make 671 milliliters of the drug, then 305 milliliters of compound A are needed.
Given that:
A certain drug is made of compound A and compound B.
There are 5 milliliters of compound A used for every 6 milliliters of compound B.
So, A and B are in the ratio of 5:6.
Let a chemist will use 5x milliliters of compound A and 6x milliliters of compound B to make 671 milliliters of the drug.
So, we equate the total amount and find the value of x.
i.e. 5x + 6x = 671
=> 11x = 671
=> x = 61
Putting the value of x = 61. We get the value of compound A and compound B.
The value of compound A = 5x = 5 x 61 = 305 milliliters.
The value of compound B = 6x = 6 x 61 = 366 milliliters.
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Why is y=mx+b the slope intercept form
Answer:
In the equation of a straight line (when the equation is written as "y = MX + b"), the slope is the number "m" that is multiplied by the x, and "b" is the y-intercept (that is, the point where the line crosses the vertical y-axis).
Answer: The equation defines the relationship between the angle of inclination of the line relative to the x-axis and the point at which the line passes through the y-axis on a graph.
Step-by-step explanation:
Imagine a line, L, that passes through the y-axis of a graph at some point B=(0,b), where the 0 is the x-coordinate of B and b is the y-coordinate of B. In this case, we will use the variable m to represent the slope of the line. Geometrically, the slope of a line is said to be tangent to its angle of inclination, the smaller of the two angles formed by the line L and the x-axis. In trigonometry, the tangent of an angle in a right triangle is defined as the ratio of the side opposite of it over the side adjacent to it. This relationship can be illustrated by constructing a right triangle where the hypotenuse is formed by the segment of the line L between the point B and an arbitrary point P somewhere along the line with the coordinates (x,y).
This triangle can be seen in the attached jpg. The side opposite of the angle of inclination is the imaginary vertical line formed between the point P and the x axis and the side adjacent to it is formed by the imaginary horizontal line between the point B and the vertical line from P. The point where these imaginary lines intersect forms the right angle of the triangle. The length of the opposite side, l1, can be expressed as the difference in y between points P and B:
l1 = y-b
Likewise, the length of the adjacent side, l2, can be expressed as the difference in x between points P and B:
l2 = x-0
The tangent of the angle of inclination, labled as [tex]\alpha[/tex] in the picture, can then be expressed as:
tan([tex]\alpha[/tex]) = [tex]\frac{(y-b)}{(x-0)}[/tex]
simplified as:
tan([tex]\alpha[/tex]) = [tex]\frac{y-b}{x}[/tex]
Because we know that slope m = tan([tex]\alpha[/tex]), we can say that
m = [tex]\frac{y-b}{x}[/tex]
solving by algebra for y,
mx + b = y or y = mx + b
in single variable calculus, the slope of a line is described as the rate of change of its y coordinates with respect to the rate of change of its x coordinates, referred to as the derivative of y with respect to x. This relationship is used to describe things like the speed of an object as it relates to the change in the objects position. The important thing to realize here is the connection between the slope, which we expressed as the difference in the y values of two points on a line over the difference in their x values, and the behavior of the coordinates of points as you move along the line.
Hope that helps! If the last bit is confusing, don't worry, as long as you understand why y=mx+b is the slope intercept form you've got the right idea.
Based on the graph, which of the following guarantees that an estimate using tangent line approximation will result in an overestimate? point of tangency near x = -2 point of tangency near x = 0 point of tangency near x = 2 point of tangency near x = 4
The value of x at which the tangent line approximation will result in an overestimate is given by:
Point of tangency near x = 0.
When does the tangent line approximation results in an underestimate and when does it results in an overestimate?The possible results for the tangent line approximation are given as follows:
Underestimate: tangent line is below the curve.Overestimate: tangent line is above the curve.The underestimate or underestimate depend on the second derivative of the function, as follows:
Second derivative positive: underestimate.Second derivative negative: overestimate.Hence, regarding the concavity, we have that the definitions are listed as follows:
Concave down: overestimate.Concave up: underestimate.On the graph given by the image at the end of the answer, the concave down point is given as follows:
x = 0.
Hence the correct option is:
Point of tangency near x = 0.
Missing InformationThe graph is given by the image at the end of the answer.
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helpppp................
Answer:
Step-by-step explanation:
Tips: All of the figures are prisms so always add prism to end.
2. Rectangular prism. Since it is a rectangle with the 3d dimensions added to it.
3. Hexagonal Prism. Since it is a hexagon with 3d dimensions added to it.
6. Triangular prism. Since it is a triangle with 3d dimensions added to it.
8. Also Triangular prism. Look above.
9. Rectangular prism. Since it is a rectangle with the 3d dimensions added to it.
10. Another Rectangular prism.Since it is a rectangle with the 3d dimensions added to it.
Ps. All the answers you created are correct!
which expression shows how to write(3^4)^2 as a product?
(3⁴)² can be written as 3² × 3⁶.
What is Exponentiation?Exponentiation is the operation of doing multiplication repeatedly and it is written in the form aᵇ.
We have to write the given expression (3⁴)² as product of two numbers.
Now, (3⁴)² = 3⁸
We have the property of exponentiation,
aⁿ × aˣ = a^(n + x)
Thus 3⁸ = 3^(2+6) = 3² × 3⁶
Hence, (3⁴)² can be expressed as 3² × 3⁶.
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Visitors to the amusement park must be at least 54 inches tall to ride the roller coaster. How tall might a visitor riding the roller coaster be?
Answer:
Step-by-step explanation:
The visitor might be exactly 54 inches or above 54 inches.
lara writes the expression 1.5x 2.75y 3. maria writes the expression 3 1.5x 2.75y. which property can be used to prove the two expressions are equivalent?
The correct property is used to prove the two expressions are equivalent is;
''Commutative property''
What is an expression?
Mathematical expression is defined as the collection of the numbers variables and functions by using operations like addition, subtraction, multiplication, and division.
Given that;
Lara writes the expression 1.5x + 2.75y + 3.
And, Maria writes the expression 3 + 1.5x + 2.75y.
Now,
Since, The commutative property states that;
a + b = b + a
So, Clearly, Here the commutative property used to prove the two expressions are equivalent, as;
⇒ 1.5x + 2.75y + 3 = 3 + 1.5x + 2.75y.
Thu, The correct property is used to prove the two expressions are equivalent is;
''Commutative property''
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A biker cycles 9 miles 2/3 of an hour. The distance here varies directly with time. What is the constant of variation (It is the biker's rate.)
The constant of variation of the distance is 13.5 miles
How to determine the constant of variation?From the question, we have the following parameters that can be used in our solution:
Distance cycled = 9 miles
Number of hours = 2/3 of an hour
From the above parameter, we can calculate the constant of variation
The constant of variation is calculated as
Constant of variation = Distance cycled/Number of hours
Substitute the known values in the above equation
So, we have the following equation
Constant of variation = 9/(2/3)
Evaluate the quotient
Constant of variation = 13.5
Hence, the constant of variation is 13.5 miles per hour
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Need help with this please
The value of 2[tex]\sqrt{12xy^{2} }[/tex] is 4y[tex]\sqrt{3x}[/tex].
According to the question,
We have the following expression:
[tex]2\sqrt{12xy^{2} }[/tex]
Now, we know that the square root of [tex]y^{2}[/tex] is y.
And the square root of 12 is [tex]2\sqrt{3}[/tex].
(More to know: we have the perfect square root of numbers. For example, the perfect square root of 36 is 6 and the perfect square root of 100 is 10. In the same way, there are perfect cube roots of numbers. For example, the perfect square root of 27 is 3.)
So, by putting the values of these terms in the square root, we have the following expression:
2*y*2[tex]\sqrt{3x}[/tex]
4y[tex]\sqrt{3x}[/tex]
Hence, the value of the given expression after solution is 4y[tex]\sqrt{3x}[/tex].
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Find the slope and the y-intercept of the line.
3x-2y=-6
Write your answers in simplest form.
slope:
3
y-intercept: -6
2
X
08
Undefined
Ś
Step-by-step explanation:
convert equation to y = mx+c:
3x-2y= - 6
3x+6=2y
y=3/2x+6/2
y=3/2x+3
gradient/slope=3/2
y intercept = 3
Please mark as brainliest :))))0
Answer:
Step-by-step explanation:
y = mx + b , where "m" is a slope and "b" is a y-intercept
~~~~~~~~~~~~~~
3x - 2y = - 6
3x - 3x - 2y = - 3x - 6
- 2y = - 3x - 6
[tex]\frac{-2}{-2}[/tex] y = [tex]\frac{-3}{-2}[/tex] x + [tex]\frac{-6}{-2}[/tex]
y = [tex]\frac{3}{2}[/tex] x + 3
Slope: [tex]\frac{3}{2}[/tex]
y-intercept: 3
Simplify -4 (x + 1) + 6x write urr answer in factored form
x = 1
Step-by-step explanation:
[tex]{ \orange{ \tt{ - 4(x + 1) + 6x}}}[/tex]
Multiply -4 with (x+1) then the Eqⁿ becomes
[tex]{ \orange{ \tt{ - 4x - 4 + 6x}}}[/tex]
Step (1):- [tex]{ \red{ \sf{combine \: like \: terms}}}[/tex]
You can see the like terms i.e. -4x and 6x. Now, add this like terms.
[tex]{ \orange{ \tt{ - 4x + 6x - 4}}}[/tex]
[tex]{ = \orange{ \tt {2x - 4}}}[/tex]
Step (2):- [tex]{ \red{ \sf{ common \: factor}}}[/tex]
Take 2 as common in 2x-4 then,
[tex]{ \orange{ \tt{2(x - 2)}}}[/tex]
[tex]{ \orange{ \tt{2x - 2 = 0}}}[/tex]
[tex]{ \orange{ \tt{2x = 2}}}[/tex]
[tex]{ \blue{ \boxed{ \purple{ \sf{x = 1}}}}}[/tex]
a home-improvement store offers a new brand of lawn food that claims to reduce the number of weeds by 30% over a different brand of lawn food. to test the claim, a homeowner plans to use the new brand of lawn food on half of his lawn and the original brand on the other half. the homeowner will count the number of weeds that appear after a month on each half of the lawn. a neighbor explains that there may be confounding variables, such as shade, that might also explain the relationship. which statement best describes the effect of the confounding variables? because of confounding variables, the homeowner should only put the new lawn food on shady spots and the original brand on sunny spots. because shade is a primary cause of weed growth, the brand of lawn food used in shady or sunny spots will not affect the number of weeds. if the half of the lawn with the new lawn food shows fewer weeds after a month, this will prove the new lawn food is better at stopping weed growth. the parts of the lawn that receive the new lawn food may also get more shade than other parts of the lawn, and the shade might also cause fewer weeds.
Answer: D
Step-by-step explanation: The part of the lawn that receive the new lawn food may also get more shade than other parts of the lawn. And the shade might also cause fewer weeds
In a group of 50 people, 20 are vegetarian. If two people are selected at random, what is the expected number of vegetarians?.
In a group of 50 people, 20 are vegetarian. If two people are selected at random, the expected number of vegetarians is 0.8.
Define mean.In mathematics, the mean is the average of a set of data, which is calculated by adding all the numbers together and then dividing the result by the total number of numbers. There are various mean types in mathematics, particularly in statistics. Each mean helps to summarize a certain set of data, frequently to help determine the overall significance of a specific data set.
Given,
In a group of 50 people, 20 are vegetarian. If two people are selected at random,
For proportion,
p = x/n
p = 20/50
p = 0.4
n = 2
Mean:
x = np
x = 2 × 0.4
x = 0.8
In a group of 50 people, 20 are vegetarian. If two people are selected at random, the expected number of vegetarians is 0.8.
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use the arithmetic sequence 12,15,18,21...
what is the equation of the nth term of the sequence
Answer:
3n+9
Step-by-step explanation:
If i toss a fair coin five times and the outcomes are ttttt, then the probability that tails appears on the next toss is.
The probability that tails appears on the next toss is 0.5
Given,
In the question:
If I toss a fair coin five times and the outcomes are TTTTT,
To find the probability that tails appears on the next toss is.
Now, According to the question:
The possible ordered outcomes are listed as elements in a sample space, which is commonly indicated using set notation.
A sequence of five fair coin flips has a sample space that contains all potential outcomes. [tex]2^3[/tex] {H, T} is the sample of a fair coin toss. {HHHHH, HHHHT, HHHTH, HHTHH, HTHHH,...…TTTTT} .
The probability of a tails result on the next flip is always equal to 0.5 It makes no difference if previous outcomes were {TTTTT} , {HHHHH} or {THTHT} In each of these and all other circumstances, the probability of the next being tails is still 0.5
Hence, the probability that tails appears on the next toss is 0.5
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What is the slope of the line whose equation is
Oslope = 2
O slope = -9
O
slope = 0
Oslope = -1/2
y = 16?
Answer: slope = 0
Step-by-step explanation:
The equation of straight line can be expressed in the form y = mx + b, which is referred to as slope intercept form.
In this equation, m represents the slope of the line, y is the y-coordinate of an arbitrary point along the line and x is the x-coordinate of the same point, and b is the location where the line intercepts the y-axis of the graph.
if y = 16, then the slope of the line, m, must be 0.
y = mx + b
y = (0)x + b
y = b
In other words, the line described by the equation y = 16 is a horizontal line that passes through the y-axis at the point (0,16).
11. Write the equation of the line in point-slope form with a slope of -2
and passes through the point (2,-9). (YELLOW)
Find the midpoint of the segment with the
following endpoints.
(8, 2) and (1, 10)
Answer:
(4.5 , 6)
Step-by-step explanation:
Finding the midpoints of segment when endpoints are given:
To find the midpoints, add the x-coordinates and divide by 2 and add the y-coordinates and divide by 2.
(8 , 2) ⇒ x₁ = 8 ; y₁ = 2
(1 , 10) ⇒ x₂ = 1 ; y₂ = 10
[tex]\sf Mipoint\left(\dfrac{x_1+x_2}{2}, \dfrac{y_1+y_2}{2}\right)[/tex]
[tex]\sf = \left(\dfrac{8+1}{2},\dfrac{2+10}{2}\right)\\\\\\=\left(\dfrac{9}{2},\dfrac{12}{2}\right)\\\\\\=(4.5,6)[/tex]
What is true of any triangle created by points u, v, and any point on line r t other than s? it will be a right triangle. it will be an acute triangle. it will be an equilateral triangle. it will be an isosceles triangle.
For any triangle created by points u, v, and any point on the line r t other than s, it will be an isosceles triangle.
Isosceles triangle, in geometry, refers to a triangle that has at least two equal length sides. The isosceles triangle sometimes is specified as having exactly two sides of equal length, and sometimes as having at least two sides of equal length. The triangle which has at least two sides of equal length includes the equilateral triangle as a special case. An isosceles triangle has two sides that are congruent to each other and the third side which is unequal to the other two sides is called the base of the isosceles triangle. The two angles opposite to the equal sides are congruent to each other. Hence, in the given situation, any triangle created by u, v, and any point on the line r t other than s, will be an isosceles triangle as the sides UR and UV will always be equal.
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find the slope (15,8),(-17,9)
Please give brainly if correct :)
Answer: -1/32
Step-by-step explanation:
Use the slope formula: y2-y1/x2-x1
Apply that:
9-8/-17-15 = 1/-32 = -1/32
During a one-month promotional campaign, Fran's Flix
gave either a free DVD rental or a
12-serving box of microwave popcorn to
new members. It cost the store $1 for each free
rental and $2 for each box of popcorn. In all, 59 new members were signed up and the
store's cost for the incentives was $103. How many of each incentive were given away?
If the store's cost for the incentives was $103.The amount of each incentive that were given away is: Free Rental 5, Box of popcorn 54.
How to find the incentive given?Let Free Rental = r
Let Box of popcorn = p
Total incentives:
r+p=59
r= 59-p Equation 1
r×1+p×2=103
r+2p=103 Equation 2
Put the value of r in (eq 2) from (eq 1)
r+2p=103 (eq 2)
59-p+2p=103
59+p=103
p=103-59
p=44
Put the value of p in (eq 1)
r=49-p...........(1)
r=49-44
r= 5
Free Rental = 5
Box of popcorn = 59 -5
Box of popcorn = 54
Therefore 5 and 54 incentive were given.
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answer the question is decreased or increased by what number
Answer:
Step-by-step explanation:
decrease by 10
Answer:
Step-by-step explanation:
increased by thirty tickets
Kylie works as a salesperson at an electronics store and sells phones and phone accessories. Kylie earns a $15 commission for every phone she sells and a $2 commission for every accessory she sells. On a given day, kylie made a total of $352 in commission and sold 6 more accessories than phones. Determine the number of phones sold and the number of accessories sold.
The number of phones sold would be 20
And, the number of accessories sold would be 26.
Used the concept of an equation that states,
An equation is a group of numerical variables and functions that have been combined using operations like addition, subtraction, multiplication, and division.
Given that,
Kylie earns a $15 commission for every phone she sells and a $2 commission for every accessory she sells.
And, On a given day, Kylie made a total of $352 in commission and sold 6 more accessories than phones.
Let us assume that,
The number of phones sold = x
And, the number of accessories sold = y
Hence, the equation becomes,
15x + 2y = 352 .. (i)
And, y = x + 6 .. (ii)
Substitute the value of y in (i);
15x + 2y = 352
15x + 2 (x + 6) = 352
15x + 2x + 12 = 352
17x + 12 = 352
17x = 352 - 12
17x = 340
x = 340/17
x = 20
From (ii);
y = x + 6
y = 20 + 6
y = 26
Therefore, The number of phones sold = 20
And, the number of accessories sold = 26
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Use the diagram below
The measure of angle KJL from the given figure is 84°.
Given that, 3(m∠LJM)=2(m∠KJL) and m∠KJM=140°.
What is an angle?An angle is formed when two straight lines or rays meet at a common endpoint. The common point of contact is called the vertex of an angle.
Here, m∠KJM=m∠LJM+m∠KJL
Now, (m∠LJM)=2/3 (m∠KJL)
140°= 2/3 (m∠KJL) + m∠KJL
⇒ [2(m∠KJL)+3(m∠KJL)]/3 = 140°
⇒ 5m∠KJL=420°
⇒ m∠KJL=420°/5
⇒ m∠KJL=84°
Hence, the measure of angle KJL from the given figure is 84°.
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A cold water pipe can fill a swimming pool in 4 hrs, and a hot water pipe can fill it in 6 hrs. If cold water pipe is turned on and hot water pipe is turned on 3 hrs later, how long will it take for the pool to be filled?
Answer: 3 hours 36 minutes
Step-by-step explanation:
You can find out that the cold pipe fills up the pool by 1/4 every hour from the question. if you turn on the cold pipe for 3 hours, the pool would be filled 3/4 before you turn on the hot water. you also can find out that the hot pipe fills up the pool 1/6 every hour. so the next hour will continue to fill up the pool 5/12 until you turn off the water. you only need to fill up the pool 1/4 more so it will take a total of 3 hours and 36 minutes to fill up.
Write your answer as a fraction in simplest form.
Answer:
17/10 (1.7)
Hope this helps!
T Mobile charges $20 for the 1st phone plan and $6 per line added. Jenny has at most $60 she can spend for family. Write an inequality to show how many lines she can have. a 20 + 6L ≤ 60 b 6 + 20L ‹ 60 c 20 + 6L > 60 d 6 + 20L ≥ 60
Answer:
A. 20 + 6L < 60
Step-by-step explanation:
It can't be B. or D. because 20L, not a thing in this problem. That leaves us with A. and C. being our only reasonable answers.
I chose A. because Jenny can't spend more than 60