4b) Work out the mean and standard deviation of the following: picture included

Note: I ended up with the simultaneous equations, which are correct according to the markscheme BUT the answers I got upon solving them were incorrect.
μ = 170 + 1.6449σ
μ = 180 - 0.8416σ

What I got after solving these were:
μ = 169.5306859
σ = 12.44864932

But according to the markscheme, I should have gotten:
μ = 176.615...
σ = 4.021...

Can someone explain to me where I've gone wrong?

4b) Work Out The Mean And Standard Deviation Of The Following: Picture IncludedNote: I Ended Up With

Answers

Answer 1

Answer:

Yes, your simultaneous equations are correct;

Solve them like so:

170 + 1.6449σ = 180 - 0.8416

2.4865σ = 10

σ = 4.0217...

μ = 170 + 1.6449(4.0217...)

μ = 176.615...

MS is correct, you must've made an error in solving or rearranging


Related Questions

At a particular school, all students participate in at least one out of three activities: debate, music, and community service. 3 students do all three activities, 21 students do two or more activities, half of all students participate in music, and the ratio of participants in debate, music, and community service, respectively, is $5:4:3$. What is the total number of students at the school

Answers

Answer:

48

Step-by-step explanation:

The given parameters are;

The activities in which the students of the school participate = 1) Debate, 2) Music, and 3) Community services

The number of students that do all three activities = 3

The number of students that do two or more activities = 21

The number of the students that participate in music = Half of the students

The ratio of the students that take part in debate, music, and community service = 5 : 4 : 3

Let x represent a common number factor of participants in each of the given three activities, we have;

5·x participate in debate, A

4·x participate in music, B

3·x participate in community service, C

We get;

The sum of the students in the school = A∪B∪C = A + B + C - A∩B - A∩C - B∩C + A∩B∩C

Given that the number of students that do two or ore activities = 21, we have;

(A∩B)∪(A∩C)∪(B∩C) = 21

However, we have;

(A∩B)∪(A∩C)∪(B∩C) = (A∩B) + (A∩C) + (B∩C) - A∩B∩C - B∩A∩C - C∩B∩A + A∩B∩C

∴ 21 = (A∩B) + (A∩C) + (B∩C) - 3 - 3 - 3 + 3

(A∩B) + (A∩C) + (B∩C) = 21 + 3 + 3 + 3 - 3 = 21 + 6 = 27

∴ -(A∩B) - (A∩C) - (B∩C) = -27

Therefore;

A + B + C - A∩B - A∩C - B∩C + A∩B∩C = 5·x + 4·x + 3·x - 27 + 3

5·x + 4·x + 3·x - 27 + 3 = 12·x - 24

The total number of students = A∪B∪C = 12·x - 24

The number of students participating in music, B = 4·x = Half the total number of students = (12·x - 24)/2

∴ 4·x = (12·x - 24)/2

8·x = 12·x - 24

12·x - 8·x = 24

4·x = 24

x = 24/4 = 6

The total number of students at the school = 12·x - 24 = 12 × 6 - 24 = 48

If the diameter of a cylinder is 18 inches, the radius of the cylinder is 9 inches.

True False

Answers

Answer:

True

Step-by-step explanation:

A cylinder has two circles as its bases, and the diameter formula is:

2r = d

So if you plug in:

2r = 18

---    ---

2     2

r = 9

So it will be true.

Hope this helped.

help please area geometry !!

Answers

Answer:

37.5 cm^2

Step-by-step explanation:

The area of a parallelogram is

A = bh  where b is the base and h is the height

A = 7.5 * 5

A = 37.5 cm^2

Answer:

A = 37.5 cm²

Step-by-step explanation:

The area of a parallelogram is calculated as

A = bh ( b is the base and h the perpendicular height )

Here b = 7.5 and h = 5 , then

A = 7.5 × 5 = 37.5 cm²

find the quantity whose 15% in 220​

Answers

Answer:

Step-by-step explanation:

[tex]\frac{15}{100}*220=\frac{15}{10}*22=3*11 = 33[/tex]

Any help, I would highly appreciate it ​

Answers

Answer:

B

Step-by-step explanation:

We are given the equation:

[tex]\displaystyle x(b-c) = y+x[/tex]

And that:

[tex]2b=3c=7[/tex]

And we want to find the value of y / x.

To start, subtract x from both sides in the first equation:

[tex]x(b-c) -x = y[/tex]

Divide both sides by x:

[tex]\displaystyle \frac{x(b-c)-x}{x}=\frac{y}{x}[/tex]

Simplify:

[tex]\displaystyle (b-c)-1 = \frac{y}{x}[/tex]

Next, in the second equation, divide everything by two:

[tex]\displaystyle b = \frac{3}{2} c = \frac{7}{2}[/tex]

Substitute:

[tex]\displaystyle \left(\frac{3}{2} c - c \right) - 1= \frac{y}{x}[/tex]

Simplify:

[tex]\displaystyle \frac{1}{2} c - 1 = \frac{y}{x}[/tex]

From the modified second equation, we can multipy both sides by 1/3:

[tex]\displaystyle \frac{1}{2} c = \frac{7}{6}[/tex]

Substitute:

[tex]\displaystyle \left(\frac{7}{6}\right) -1 = \frac{y}{x}[/tex]

Subtract:

[tex]\displaystyle \frac{y}{x} = \frac{7}{6} - \frac{6}{6} = \frac{1}{6}[/tex]

Therefore, our answer is B.

How do you express a gain of 4 yards in a football game as a rational number?


OA 4.5 yards
OB. 4 yards
OC. yards
OD. - yards
OE-4 yards

PLEASE HELP​

Answers

Answer:

B- 4 yards

4 is a rational number along with the number of yards gained.

According to the rules of Major League Baseball, the infield must be 30 feet by 30 feet in a diamond shape with perpendicular (90°) corners. Answer the following questions regarding the shape of the infield.​

Answers

Answer:

No Major League ballparks are exactly alike, but certain aspects of the field of play must be uniform across baseball.

The infield must be a square that is 90 feet on each side, and the outfield is the area between the two foul lines formed by extending two sides of said square (though the dirt portion of the field that runs well past the 90-foot basepaths in all Major League parks is also commonly referred to as the infield). The field must be constructed so that the bases are the same level as home plate.

The rulebook states that parks constructed by professional teams after June 1, 1958, must have a minimum distance of 325 feet between home plate and the nearest fence, stand or other obstruction on the right- and left-field foul lines, and 400 feet between home plate and the nearest fence, stand or other obstruction in center field. However, some clubs have been permitted to construct parks after that date with dimensions shorter than those specified.

The pitcher's plate must be a 24-inch by 6-inch slab of whitened rubber that is 10 inches above the level of home plate and 60 feet, 6 inches away from the back point of home plate. It is placed 18 inches behind the center of the mound -- which is erected within an 18-foot diameter circle -- and surrounded by a level area that is 5 feet by 34 inches. The slope of the pitcher's mound begins 6 inches in front of the pitcher's plate and must gradually decrease by 1 inch every foot for 6 feet in the direction of home plate.

Home plate is a 17-inch square of whitened rubber with two of the corners removed so that one edge is 17 inches long, two adjacent sides are 8 1/2 inches each and the remaining two sides are 12 inches each and set at an angle to make a point. The 17-inch side faces the pitcher's plate, and the two 12-inch edges coincide with the first- and third-base lines. The back tip of home plate must be 127 feet, 3 and 3/8 inches away from second base.

The other bases must be 15-inch squares that are between 3 and 5 inches thick, covered by white canvas or rubber and filled with soft material.

Step-by-step explanation:

Select the false statement
A. Vertical angles are always congruent
B.Vertical angles are sometimes complimentary
C.Two right angles are always supplementary
D. Angles that form a linear pair are sometimes supplementary. Plz answer ASAP

Answers

Answer: D. Angles that form a linear pair are sometimes supplementary.

That is not true, linear pairs are always supplementary.

Answer:

D. Angles that form a linear pair are sometimes supplementary.

~OAmalOHopeO

The average age of a preschool class is 4.5 years old. If there is one 3-year-old, five 5-year-olds, and two other children both of the same age, what is the age, in years, of the other two children?

Answers

Answer:

3.1

Step-by-step explanation:

5 x5 =25

25+3=28

the other children are 4 years old

A regular square pyramid has a slant height of 5 in and a base area of 49 in2. Find the surface area of the pyramid. ------------------------------------------------------------------------------------------- 171.5 square inches 70 square inches 119 square inches 245 square inches

Answers

Answer:

C: 119 square inches

Step-by-step explanation:

We are given;

Slant height; L = 5 in

Base area; B = 49 in²

Since it's a square pyramid, the base portion has a square shape.

Thus, area of base = x²

Where x is a side of the square.

Thus;

x² = 49

x = √49

x = 7

Perimeter of base = 7 × 4 = 28 in

Area of pyramid = ½PL + B

Plugging in the relevant values;

Area of pyramid = (½ × 28 × 5) + 49

Area of pyramid = 119 in²

Two friends go to a Mexican restaurant for lunch. One friend orders 1 soft taco and
3 burritos and his bill was $8.75. The other friend's bill was $10.00 and he ordered 4
soft tacos and 2 burritos. What is the cost of a taco and what is the cost of a
burrito?
The cost of a taco is:
The cost of a burrito is:

Answers

Answer:

cost of a taco: $1.25

cost of a burrito: $2.50

Step-by-step explanation:

Let the cost of a taco be $t and the cost of a burrito be $b.

t +3b= 8.75 -----(1)

4t +2b= 10

Divide both sides by 2:

2t +b= 5

Making b the subject of formula:

b= 5 -2t -----(2)

Substitute (2) into (1):

t +3(5 -2t)= 8.75

Expand:

t +3(5) +3(-2t)= 8.75

t +15 -6t= 8.75

t -6t= 8.75 -15

-5t= -6.25

t= -6.25 ÷(-5)

t= 1.25

Substitute t= 1.25 into (2):

b= 5 -2(1.25)

b= 5 -2.5

b= 2.50

Thus, the cost of a taco is $1.25 and the cost of a burrito is $2.50.

What is an
equation of the line that passes through the points (-3,-1) and (-4,-4)

Answers

Answer:

y= 3x+8

Step-by-step explanation:

not a 100% sure...

sry if its wrong

(try using Math-way, its rly helpful)

Answer:

Step-by-step explanation:

y=mx+b

To find slope: -4+1/-4+3

Slope=3

y=3x+b

Plug in either points ,as an example, i'll plug in (-3,-1)

-1=3(-3)+b

-1=-9+b

8=b

Finished formula: y=3x+8

The length of a small rectangular room is "6 more than the width" and the area of the room is 27 square units. Which of the following represents the dimensions of the room?

Answers

Step-by-step explanation:

sL=6+W

A=27square

A=L×W

=(6+w) ×W

simplify (2^2×4^-2)×5^8+2+3^0​

Answers

Here you go
I am sorry if it’s wrong


This is my best
Sorry if missed it.

PLEASE HELP! I HAVE BEEN AT THIS FOR A LONG TIME!.

For each investement, 25 000 is deposited in an account. How much is each payment?

(a. 8% per annum, compounded annually, with annual payments starting in a year.

Answers

Answer:

Annual payment wil be 2,001 and total amount after compounded annually will be 27,001

mary stated that 2.01 x 10⁶ is less than 4.8 x 10⁴ because 2.01 is less than 4.8. what was mary's mistake ?

I'm horrible at scientific notation so some help would be nice. =]​

Answers

Answer:

Step-by-step explanation:

Scientific notation is always written as a number between 1 and 9.9999999 repeating. There follows a power of 10. I'm not sure which answer would help you see it clearer but

4.8 * 10^4 the decimal is shifted 4 places the right which is 48000 where you have no numbers, you use zeros.

2.01 * 10^6 means that you shift the decimal 6 places to the right.

2010000

So 2 million is larger than 48 thousand.

The other way to do it is just to look at the power. 6 is more than 4. 6 describes the number of places you move. So does 4. 6>4 so that's the larger number.

After two people answer one of my questions, how do I give brainlyist to one of them?

Answers

Vas happenin!
Hope your day is going well

Once two people answer your question there at the top of the question that they answer should have a crown and the words mark the Brainliest. Then it will go yellow when you mark it and it will also give you points

do what you want ok and choose

Please help me ASAP I’m stuck on these questions

Answers

Answer:

4, yes through the middle    5, yes through the middle 6, yes through the middle  all of them reflect from the center

Step-by-step explanation:

_(9)=(2(1-2(2)^(9)))/(1-2(2))


PLEASE HELP ME OUT.

Answers

Answer:

the answer = um ok

Step-by-step explanation:

Find the general solution for:-

[tex]sin\:x \:cos\: 3x+cos\:x\: sin\:3x=tan140[/tex]


~Please show your work
~Thank you!

Answers

Answer:

[tex] \rm \displaystyle x \approx \bigg \{ {59.3}^{ \circ} + \frac{n\pi}{2} , - {14.3}^{ \circ} + \frac{n\pi}{2} \bigg \}[/tex]

Step-by-step explanation:

we would like to solve the following trigonometric equation:

[tex] \rm \displaystyle \sin(x) \cos(3x) + \cos(x) \sin(3x) = \tan( {140}^{ \circ} ) [/tex]

the left hand side can be rewritten using angle sum indentity of sin which is given by:

[tex] \rm \displaystyle \sin( \alpha + \beta ) = \sin( \alpha ) \cos( \beta ) + \cos( \alpha ) \sin( \beta ) [/tex]

therefore Let

[tex] \alpha = x[/tex][tex] \beta = 3x[/tex]

Thus substitute:

[tex] \rm \displaystyle \sin(x + 3x) = \tan( {140}^{ \circ} ) [/tex]

simplify addition:

[tex] \rm \displaystyle \sin(4x) = \tan( {140}^{ \circ} ) [/tex]

keep in mind that sin(t)=sin(π-t) saying that there're two equation to solve:

[tex] \begin{cases} \rm \displaystyle \sin(4x) = \tan( {140}^{ \circ} ) \\ \\ \displaystyle \sin(\pi - 4x) = \tan( {140}^{ \circ} ) \end{cases}[/tex]

take inverse trig and that yields:

[tex] \begin{cases} \rm \displaystyle 4x= { \sin}^{ - 1} ( \tan( {140}^{ \circ} ) ) \\ \\ \displaystyle \pi - 4x = { \sin}^{ - 1}( \tan( {140}^{ \circ} ) ) \end{cases}[/tex]

add π to both sides of the second equation and that yields:

[tex] \begin{cases} \rm \displaystyle 4x= { \sin}^{ - 1} ( \tan( {140}^{ \circ} ) ) \\ \\ \displaystyle - 4x = { \sin}^{ - 1}( \tan( {140}^{ \circ} ) ) + \pi\end{cases}[/tex]

sin function has a period of 2nπ thus add the period:

[tex] \begin{cases} \rm \displaystyle 4x= { \sin}^{ - 1} ( \tan( {140}^{ \circ} ) ) + 2n\pi\\ \\ \displaystyle - 4x = { \sin}^{ - 1}( \tan( {140}^{ \circ} ) ) + \pi + 2n\pi\end{cases}[/tex]

divide I equation by 4 and II by -4 which yields:

[tex] \begin{cases} \rm \displaystyle x= \frac{ { \sin}^{ - 1} ( \tan( {140}^{ \circ} ) ) }{4} + \frac{n\pi}{2} \\ \\ \displaystyle x = - \frac{{ \sin}^{ - 1}( \tan( {140}^{ \circ} ) ) + \pi}{4} - \frac{n\pi}{2} \end{cases}[/tex]

recall that,-½(nπ)=½(nπ) therefore,

[tex] \begin{cases} \rm \displaystyle x= \frac{ { \sin}^{ - 1} ( \tan( {140}^{ \circ} ) ) }{4} + \frac{n\pi}{2} \\ \\ \displaystyle x = - \frac{{ \sin}^{ - 1}( \tan( {140}^{ \circ} ) ) + \pi}{4} + \frac{n\pi}{2} \end{cases}[/tex]

by using a calculator we acquire:

[tex] \begin{cases} \rm \displaystyle x \approx - {14.3}^{ \circ} + \frac{n\pi}{2} \\ \\ \displaystyle x \approx {59.3}^{ \circ} + \frac{n\pi}{2} \end{cases}[/tex]

hence,

the general solution for: for the trig equation are

[tex] \rm \displaystyle x \approx \bigg \{ {59.3}^{ \circ} + \frac{n\pi}{2} , - {14.3}^{ \circ} + \frac{n\pi}{2} \bigg \}[/tex]

graph the equation y=5/7x

Answers

Answer:

Step-by-step explanation:

If you to math pap it shows u

If cos(27) =p, express sin(27) in terms of p

Answers

Answer:

√(p²-1)

Step-by-step explanation:

sin (27°) = √(p²-1) / 1

= √(p²-1)

Identify the equation of the circle that has its center at (16, 30) and passes through the origin

Answers

To solve this question, we have to find the equation of the circle with given center and where it passes. Doing this, we get that the equation of the circle is:

[tex](x - 16)^2 + (y - 30)^2 = 1156[/tex]

Equation of a circle:

The equation of a circle with center [tex](x_0, y_0)[/tex] and radius r is given by:

[tex](x - x_0)^2 + (y - y_0)^2 = r^2[/tex]

Center at (16, 30)

This means that [tex]x_0 = 16, y_0 = 30[/tex]

Thus

[tex](x - 16)^2 + (y - 30)^2 = r^2[/tex]

Passes through the origin:

We use this to find the radius squared, as this means that [tex]x = 0, y = 0[/tex] is part of the circle. Thus

[tex](x - 16)^2 + (y - 30)^2 = r^2[/tex]

[tex](0 - 16)^2 + (0 - 30)^2 = r^2[/tex]

[tex]r^2 = 16^2 + 30^2 = 1156[/tex]

Thus, the equation of the circle is:

[tex](x - 16)^2 + (y - 30)^2 = 1156[/tex]

For another example to find the equation of a circle, you can look at https://brainly.com/question/23719612

A baker finds several new recipes to try. Of the new recipes, there are 11 for cookies, 10 for muffins, and 4 for cakes. If the baker selects a recipe at random, what is the probability the recipe is for a cake?

Answers

Answer:

4/25

Step-by-step explanation:

All the amount of recipes is 11+10+4=25 . There are 4 recipes for cakes

so probability is 4/25

A sports scientist has made the formula below that gives the energy in joules provided,
e
per
ml
,
a
consumed of a power drink.



e=a×0.2



Substitute in
660
for the amount consumed,
a
, in an energy shake and give the energy provided,
e
.

Answers

Gotta space it better but I think it’s .35

Is the collection of nice Nepali songs a set ? Why ?​

Answers

Answer:

kun vannu vayeko hoo bujena ni saathi yo question complete xa ta.

Answer:

Is the collection of nice Nepali songs a set ? Why ?

=⟩ yes the collection of nice Nepali songs a set Because it can be collected on bracket .

Find the 8th term of the geometric sequence 7,−21,63,

Answers

Answer:

8th term is -15309

Step-by-step explanation:

[tex]{ \boxed{ \bf{u_{n} = a( {r}^{n - 1} ) }}} \\ { \tt{u_{8} = 7( {( - 3)}^{8 - 1}) }} \\ { \tt{u_{8} = 7( - 2187)}} \\ { \tt{u _{8} = - 15309}}[/tex]

r is the common difference, r = -21/7 = -3

Answer:

a₈ = - 15309

Step-by-step explanation:

The nth term of a geometric sequence is

[tex]a_{n}[/tex] = a₁ [tex](r)^{n-1}[/tex]

where a₁ is the first term and r the common ratio

Here a₁ = 7 and r = [tex]\frac{a_{2} }{a_{1} }[/tex] = [tex]\frac{-21}{7}[/tex] = - 3 , then

a₈ = 7 × [tex](-3)^{7}[/tex] = 7 × - 2187 = - 15309

The graph below shows a proportional relationship between y and x .
What is the constant of proportionality?
y/x?

Answers

Answer:

49/1

Step-by-step explanation:

The point is on (1,49)

See pic below! Need help solving

Answers

Answer:

383.54 m

Step-by-step explanation:

The length of the training track running around the field = circumference of the circle formed by the two semicircles + 2(length of the rectangle)

The two semicircles forms a fill circle with diameter (d) = width of rectangle = 61 m

Length of rectangle (L) = 96 m

π = 3.14

The length of the training track running around the field = πd + 2(L)

Substitute the values

The length of the training track running around the field = 3.14*61 + 2(96)

= 191.54 + 192

= 383.54 m

Since opening night, attendance at Play A has increased steadily, while attendance at Play B first rose and then fell. Equations modeling the daily attendance y at each play are shown below, where x is the number of days since opening night. On what day(s) was the attendance the same at both plays? What was the attendance?

Play A: y=25x+136
Play B: y=-x^2+44x+76

Answers

Answer: Day 4 and 15

Step-by-step explanation:

Set up system of equations:

[tex]25x+136=-x^2+44x+76[/tex]

Simplify:

[tex]x^2-19x+60=0[/tex]

Factor: Both factors must be positive as the days can only be natural numbers.

[tex](x-15)(x-4)=0[/tex]

x=4,15

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