A sample of 12 measurements has a mean of 16.5, and a sample of 15 measurements has a mean of 18.6. Find the mean of all 27 measurements

Answers

Answer 1

Answer: [tex]17.67[/tex]

Step-by-step explanation:

Given

Sample  of 12 measurements has a mean of 16.5 and

a sample of 15 measurements has a mean of 18.6

Take [tex]\bar{x_1},n_1[/tex] be the mean and no of measurements

and [tex]\bar{x_2},n_2[/tex] be the mean and no of measurements in second case

[tex]\therefore \bar{x_1}=\dfrac{\sum a_1}{n_1}\\\\\Rightarrow \sum a_1=\bar{x_1}\times n_1\\\\\Rightarrow \sum a_1=198\quad \ldots(1)[/tex]

Similarly,

[tex]\therefore \bar{x_2}=\dfrac{\sum a_2}{n_2}\\\\\Rightarrow \sum a_2=\bar{x_2}\times n_2\\\\\Rightarrow \sum a_2=279\quad \ldots(2)[/tex]

Mean of 27 measurements

[tex]\Rightarrow \bar{x_3}=\dfrac{\sum a_1+\sum a_2}{n_1+n_2}\\\\\Rightarrow \bar{x_3}=\dfrac{198+279}{12+15}\\\\\Rightarrow \bar{x_3}=\dfrac{477}{27}\\\\\Rightarrow \bar{x_3}=17.67[/tex]


Related Questions

An aeroplane travels on a bearing of 295o so that it is 200 km west of its starting point. How far has it travelled on this bearing?
please use diagrams to explain

Answers

Answer: Approximately 221 km

The more accurate value is roughly 220.675583792499 km but even that isn't an exact value.

===============================================

Explanation:

Refer to the diagram below.

The plane starts at point A, which is the origin (0,0)

Directly north is the bearing 0 degrees, which it sometimes written as triple zeros and a degree symbol at the end, so we'd write 000° to mean directly north.

Let's say we face directly north. When turning clockwise (turn toward the east), the bearing angle increases. That means directly east is the bearing 090° and 180° is directly south.

The bearing 270° is directly west. Another 25 degrees gets us to 270+25 = 295°

This plane is facing the northwest direction, as the diagram indicates below (the plane is aimed at point C while it's located at point A initially).

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

Triangle ABC has the horizontal component AB = 200 km, since we're told that the plane is 200 km west of its starting point (and some unknown distance north of the starting point).

We use the cosine ratio to help determine the hypotenuse length AC

cos(angle) = adjacent/hypotenuse

cos(A) = AB/AC

cos(25) = 200/x

x*cos(25) = 200

x = 200/cos(25)

x = 220.675583792499 which is approximate.

x = 221

I'm rounding to the nearest whole number since every other value given to you is a whole number. Round as your teacher instructs.

This means the plane is roughly 221 km away from its starting point. In other words, side AC is about 221 km long.

5 - 2x^2 = -15 solve the question using inverse operations

Answers

Answer:

x= √10 and x= -√10

Step-by-step explanation:

first look to isolate the term with the variable on one side

-5 +5 -2x² = -5 -15; subtract 5 from both sides(inverse of addition)

-2x² = -20; divide both sides by -2 (inverse of multiplication)

x² = 10; square root both sides (the inverse of raising to power of 2)

√x² =√10

x =±√10

Find the unknown length in the picture below please help

Answers

Answer:

x = 12.65

Step-by-step explanation:

The angle between radius and tangent is 90°

Given diameter is 6, so radius = 3.

Then we use Pythagoras theorem

Name the marked angle in 2 different ways.

Answers

Angle LNM and angle MNL

pls follow and mark brainliest

Find the area of the triangle. Round your answer to the nearest tenth.
B
54 yd
270
А
54 yd
с
a. 742.9 yd?
b. 1,458 yd?
C. 1,323.8 yd?
d. 661.9 yd?

Answers

Answer:

here is the answer bae. Feel free to ask for more

how do u factor..
x^2 + 10× - 2400 = 0 ​

Answers

Answer:

[tex]{ \bf{ {x}^{2} + 10x - 2400 = 0}} \\ { \bf{ \red{it \: has \: no \: rational \: factors}}} \\ x = - 54.2 \: \: and \: \: 44.2[/tex]

x^2+10•-2400=0
x^2-24000=0
x^2=24000
take the square root of 24000

How many quarters are there in 5 1
? ?
2​

Answers

Answer:

yes

Step-by-step explanation:

51 divided by 25

A) m + n
B) 0
C) m - 1
D) -(m+n)

Answers

Answer:

D

Step-by-step explanation:

Lsh=rhs

U solve using algebra

Which value of a would make the following expression completely factored?

x²-a

A.12
B.36
C.49
D.81

Answers

Answer:

The answer is 12.               

12 is not a perfect square like the others.      

helppppppppppppppppp

Answers

Answer:

Click the third one.

Answer:

3rd one

Step-by-step explanation:

Mark me brainliest pls

Hope this helps!

A room has a length of 12 metres and width of 5 metres. What is the area of the room?
Working out please

Answers

Answer:

60 sq.m

Step-by-step explanation:

Given,

Length of the room = 12m

Width of the room = 5m

Therefore,

Area of the room = l × w

= 12m × 5m

= 60 sq.m (Ans)

What triangles are similar to triangle AED? Explain or show your reasoning.

Answers

Answer:

DCE is similar to AED

EBA is similar to AED

AFE is similar to AED

EFD is similar to AED

Step-by-step explanation:

Triangle AED:

D=53(alternate interior angle)

A=180-90-53=37 (angle of triangle)

AA similarity criterion

DCE is similar to AED

angle BEA=180-90-53=37=angle A of AED

Thus: AA similarity criterion:

EBA is similar to AED

The diagonal of parallelogram(here:rectangle) cut it into 2 congruent triangles

Thus:

EBA is congruent to AFE

EBA is congruent to AFEDCE is congruent to EFD

Congruent triangles are similar

Conclusion:

DCE is similar to AED

EBA is similar to AED

AFE is similar to AED

EFD is similar to AED

Please give brainliest if it helps

The triangles are similar to triangles AED are DCE is similar to AED, EBA is similar to AED, AFE is similar to AED, EFD is similar to AED.

We have to determine

What triangles are similar to triangle AED?

According to the question

Alternate interior angles are formed when a transversal passes through two lines.

The angles that are formed on opposite sides of the transversal and inside the two lines are alternate interior angles.

In the triangle AED:

The angle is equal to 53.

Then,

A=180-90-53=37

DCE is similar to AED.

Here EBA, DCE, EF, D, and AFE bc it doesn’t matter about the size it matters about the angle whether it stays the same and you can clearly see that angle b, and f, angle, c, and angle e are all 90 degrees making the triangles I listed similar to triangle AED.

Hence, The triangles are similar to triangles AED are DCE is similar to AED, EBA is similar to AED, AFE is similar to AED, EFD is similar to AED.

To know more about Triangle click the link given below.

https://brainly.com/question/23919428

2) through:(-1,-1), slope = -4

Answers

? Hm maybe the slope would be -4 over 1

find the perimeter of this figure to the nearest hundredth. Use 3.14 to approximate π.​

Answers

Answer:

P = 40.56 ft.

Step-by-step explanation:

Answer:

40.56

Step-by-step explanation:

Can you please help me. It says to find each product

Here is the question
There is a picture

Answers

Answer:

-3/5

Step-by-step explanation:

7 * -3/7 * 1/5

Rewritng

7/7 * -3/5 *1

Simplifying fractions

1 * -3/5 *1

-3/5

what is the constant of proportionality in the equations 3y=2X?

Answers

Answer:

the coefficient of x is 2/3 which is the constant.

Triangle NJK is similar to triangle LMK by​

Answers

Answer:

B

Step-by-step explanation:

SAS cuz ML~NJ and K is common angle

the graph of y=-3x+4 is?

Answers

Answer:

B

Step-by-step explanation:

that is a linear equation, therefore it makes a line, eliminating choices C and D.

Lines can literally Any x or y. So it would be B, a set of all the solutions to the equations.

consider the following sequence at 87;84;81 which term will be the first negative term in the sequence​

Answers

Answer:

"31st in the sequence"

87/3 = 29 ..   29 subtractions needed to get to zero

the 30th position in the sequence will be zero

the 31st is the first negative term

1 87

2 84

3 81

4 78

5 75

6 72

7 69

8 66

9 63

10 60

11 57

12 54

13 51

14 48

15 45

16 42

17 39

18 36

19 33

20 30

21 27

22 24

23 21

24 18

25 15

26 12

27 9

28 6

29 3

30 0

31 -3

Step-by-step explanation:

What type of function is represented by the table of values below?
х
1
2
3
4
5
у
2
4
8
16
32
A. exponential
B. quadratic
C. cubic
D. linear

Answers

Answer:

Step-by-step explanation:

This is exponential. I'll show you how I found it. After many attempts at other types of functions, I realized the points were either forming a quadratic or an exponential. Definitely not a line.

the standard form of an exponential function is

[tex]y=a(b)^x[/tex] so we sub in coordinates from the table to determine what the equation is and then test it on another set of points to see if it works. Using the first coordinate of (1, 2):

[tex]2=a(b)^1[/tex] so

[tex]a=\frac{2}{b}[/tex] . The next  coordinate is (2, 4), so:

[tex]4=\frac{2}{b}(b)^2[/tex] which simplifies down to

4 = 2b so

b = 2. Now we plug in 2 for b and solve for a:

a = 2/2 which is 1. So the equation, if this is exponential, is

[tex]y=1(2)^x[/tex] Let's test the next point in line and see if it works, (3, 8):

[tex]8?=?1(2)^3[/tex] and yes, 8 is equal to 2 cubed. And the next point says that 16 should equal 2 to the 4th, and it does, as well. So this is exponential...growth to be specific.

If pi is rounded to a whole number, what is a reasonable estimate for the circumference of a circle with a diameter of 18 cm?

57 cm
50 cm
54 cm
56 cm

Answers

Answer:

54 cm

Step-by-step explanation:

Hi there!

1) Round pi

π = 3.14159265...

Rounded to a whole number ⇒ 3

2) Determine the circumference

C = πd where d is the diameter

Plug in the diameter

C = 18π

Plug in π

C = 18(3)

C = 54

Therefore, a reasonable estimate for the circumference of this circle would be 54 cm.

I hope this helps!

Help!! Stuck on math problem!
Fast answers are appreciated, thanks :)
The graph of the function has a vertical asymptote of x = ______
The graph of the function has a horizontal asymptote of y = ______

Answers

Vertical Asymptotes:
x=0
x=0
Horizontal Asymptotes:
y=0
y=0
No Oblique Asymptotes

What is the volume of the following cylinder? Do not round your answer. (Use 3.14 for π.)



volume = ____yd3

Answers

Answer: 1696.46003yds^3

Hope this helped!! Have a nice day :))

Answer: 1962.5

Step-by-step explanation:  Just did this question it's right hope this helps

https://hegartymaths.com/assessment
Several points are given on the graph below.
a) A, B and C are three corners of a rectangle.
Write the coordinates of the other corner.
b) C, D and E are three vertices of a rhombus.
Write the coordinates of the other vertex.
5 ty
А.
В.
4
.
3
2
1.
-5
-4
-3
-1
2
3
4
-2
E
5
-1
D.
-2
-3
-4
-5

Answers

Answer:

??????????

Step-by-step explanation:

Answer:

need more clarification

Step-by-step explanation:

?????????????????????????????????????????????????????????????????????

A. write the ratio of girls to boys in the class with 12 girls and 15 boys. reduce to the lowest terms.
B. use the information from part A to estimate the number of girls in the school if there are a total of 1350 students in the whole school and in part A is representative of all classes in the school
WILL GIVE BRAINLIEST

Answers

Answer:

A. 4:5

B. 600 girls

Step-by-step explanation:

A. g : b = 12 : 15 = 4 : 5

B. the numbers of girls = 4/(4+5) × 1350

= 4/9 × 1350 = 600

Find the missing side of the triangle and leave the answer in simplest radical form

Answers

Answer:

it would be radical 7

15 = x²+ 8

x²= 15 - 8

x²= 7 >>>>> radical 7 = x

Step-by-step explanation:

hope it helps

Answer:

x = √7.

Step-by-step explanation:

Using the Pythagoras theorem:

x^2 = (√15)^2 - (2√2)^2

x^2 = 15 - 8

x = √7.

yo brainly bolws and 2+2 is 4

Answers

Answer:

chese

Step-by-step explanation:

Cheese is a dairy product, derived from milk and produced in wide ranges of flavors, textures and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. During production, the milk is usually acidified and the enzymes of rennet (or bacterial enzymes with similar activity) are added to cause the milk proteins (casein) to coagulate. The solids (curd) are separated from the liquid (whey) and pressed into final form.[1] Some cheeses have aromatic molds on the rind, the outer layer, or throughout. Most cheeses melt at cooking temperature.

Answer:

2+2=4

Step-by-step explanation:

Bro, u serious?

What is the first step in solving for w in the equation 3W + 5 = 14?

Answers

subtract 5 from both sides so that you can can 3W by itself and then you divide both sides by 3W and you should get w=3

Find m angle f.
A. 88
B. 28
C. 62
D. 70

Answers

Try 62 but I’m not 100%

help -------------------------

Answers

Answer:

(A) -3 ≤ x ≤ 1

Step-by-step explanation:

The given function is presented as follows;

h(x) = x² - 1

From the given function, the coefficient of the quadratic term is positive, and therefore, the function is U shaped and has a minimum value, with the slope on the interval to the left of h having a negative rate of change;

The minimum value of h(x) is found as follows;

At the minimum of h(x), h'(x) = d(h(x)/dx = d(x² - 1)/dx = 2·x = 0

∴ x = 0/2 = 0 at the minimum

Therefore, the function is symmetrical about the point where x = 0

The average rate of change over an interval is given by the change in 'y' and x-values over the end-point in the interval, which is the slope of a straight line drawn between the points

The average rate of change will be negative where the y-value of the left boundary of the interval is higher than the y-value of the right boundary of the interval, such that the line formed by joining the endpoints of the interval slope downwards from left to right

The distance from the x-value of left boundary of the interval that would have a negative slope from x = 0 will be more than the distance of the x-value of the right boundary of the interval

Therefore, the interval over which h has a negative rate of change is -3 ≤ x ≤ 1

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