I need a lil help here (18 points!!!!!)

From the combined standard deviation, with the mean, and standard

deviation of the data sets, the required variance can be found.

Reasons:

The given data information are;

Mean of the first set of observation, [tex]\overline x_1[/tex] = 9.0

Standard deviation of the the first set, σ₁ = 4.0

Sample size of second observation, n₂ = 20

Mean of second sample, [tex]\overline x_2[/tex] = 10

Standard deviation of the combined set, σ₁₂ = 3.0

Sample size of combined set of observation, n₂ = 35

Solution:

The number of elements in the second sample, n₁ = 35 - 20 = 15

The standard deviation of the combined set is given by the formula;

[tex]{\sigma_{12}} = \mathbf{\sqrt{\dfrac{n_1 \cdot \left ( \sigma^2_{1}-d_1^2 \right ) + n_2 \cdot \left ( \sigma^2_{2}-d_2^2 \right )}{n_{1}+n_{2}}}}[/tex]

Where;

[tex]\overline x_{12} =\mathbf{\dfrac{n_1 \cdot \overline x_1 +n_2 \cdot \overline x_2 }{n_1 + n_2}}[/tex]

Therefore;

[tex]\overline x_{12} =\dfrac{15 \times 9.0 +20 \times10.0 }{15 + 20} = \dfrac{67}{7}[/tex]

d₁ = [tex]\mathbf{\overline x_{12}}[/tex] - [tex]\mathbf{\overline x_1}[/tex]

[tex]d_1 = \dfrac{67}{7} - 9.0 = \dfrac{4}{7}[/tex]

d₂ = [tex]\mathbf{\overline x_{12}}[/tex] - [tex]\mathbf{\overline x_2}[/tex]

[tex]d_2 = \dfrac{67}{7} - 10.0 = -\dfrac{3}{7}[/tex]

Therefore;

[tex]3=\sqrt{\dfrac{15 \times \left ( 4.0^2-\left(\dfrac{4}{7}\right) ^2 \right ) + 20 \cdot \left ( \sigma^2_{2}-\left(-\dfrac{3}{7}\right) ^2 \right )}{15+20}}[/tex]

Solving gives;

[tex]Variance, \ \sigma^2_2 = \mathbf{\dfrac{{117} }{28}}[/tex]

[tex]\mathrm{The \ variance \ of \ the \ second \ set, \ \sigma_2^2} = \dfrac{{117} }{28} = 4\dfrac{5}{28}[/tex]

Learn more here:

https://brainly.com/question/16869429

Answer:

y=-3x-1

Step-by-step explanation:

Answer:

I believe the correct option would be C, 2p-4. I hope this helps you! :)

Answer:

C. 2p-4

Step-by-step explanation:

Answer:

Hello, the simplified expression would be:

7x + 6

Answer:

[tex]7abc^{2}[/tex]

Step-by-step explanation:

Answer:

after a dry periods lasting many years only a few individuals of a tree population survive and then produce drought tolerant offspring.

Step-by-step explanation:

The total time that should be taken by him to finish the book is 3.9 hours.

Given that,

Based on the above information, the time taken should be

[tex]= 375 \times 20 \div 32[/tex]

= 234.375 minutes

Now in hours it should be

[tex]= 234.375 \div 60[/tex]

= 3.9 hours

Therefore we can conclude that the total time that should be taken by him to finish the book is 3.9 hours.

Learn more: brainly.com/question/22271063

The derivative of:

[tex]f(x) = ( {3x}^{2} + 2x - 1) 6[/tex]

is....

[tex]6( {3x}^{2} + 2x - 1)5(6x + 2)[/tex]

Hope this helped you- have a good day bro cya)

The value of each scarf from the sales will be $4.50.

Since Lucy spent $10.50 of her earnings on a used sweater and she had $7.50 remaining, the total amount that she made from the sales will be:

= $10.50 + $7.50

= $18.00

Since she sold 4 scarves, the cost of each scarf will be:

= $18.00 / 4

= $4.50

Therefore, the value of each scarf will be $4.50.

Read related link on:

https://brainly.com/question/25225698

Answer:

A frequency distribution table lists the data values, as well as the number of times each value appears in the data set. A histogram is a display that indicates the frequency of specified ranges of continuous data values on a graph in the form of immediately adjacent bars.

Step-by-step explanation:

Answer:

perimeter: 20.1

area: 22.1

Step-by-step explanation:

Answer:

The formula to find the are of a parallelogram is = base x height

so the base is 3 1/4 x the height is 6. so now it will be

3 1/4 x 6

you now multiply it to get the area.

So the area I am getting for this is 16 1/2 cm2.

It might be wrong but there you go.

Make as brainiest

Answer:

Step-by-step explanation:

74’F

Answer:

The range of possible temperatures in the house (in degrees Fahrenheit) is 60° F ≤ T ≤ 74°F

Step-by-step explanation:

To Find:

The range of possible temperatures in the house

Solution:

Given:

Thermostat is set to 70 °

Also actual temperature may by a much of 4°

If the temperature is 4°F lower, and actual temperature = 70°- 4° = 66° F

If the temperature is 4°F higher, actual temperature = 70°+4° = 74°

Therefore, The range of possible temperatures in the house (in degrees Fahrenheit) is 60° F ≤ T ≤ 74°F

Answer:

are there any equations for this possibly? and if not it is just a smaller scale version of the dilated trapezoid.

Answer:

$101.45

Step-by-step explanation:

change 17% to .17 then multiply it by 86.71=14.74 then add that to 86.71 and you get your answer $101.45

Answer:

hairdresser cuts 8 inches

Step-by-step explanation:

32 ÷4 =8

Answer:

x=26

Step-by-step explanation:

x+11+2x+1+90=180 [Angles in a straight line]

3x=180-102

x=78/3

x=26

or,

x+11+2x+1=90 [Complementary angles]

3x=90-12

x=78/3

x=26

Answer:

D. 19.87 acres

Step-by-step explanation:

do not put heart if wrong and put heart if correct

Answer:

the first one

Step-by-step explanation:

1/2 and 1/5 common denominator is 10

Answer:

22.28

Step-by-step explanation:

first add the decimals then the other number.

Answer:

see explanation

Step-by-step explanation:

Given x < 5

The graph will have an open circle at 5 indicating that x is not equal to 5, which would be a closed circle.

The ray will move to the left since values less than 5 are to the left of 5

Answer:Please see explanation

Step-by-step explanation:

What are the characteristics of the graph of the inequality x < 4.5?

The answer is The ray will move to the left.

It will use an open circle.

Please votes me 5 stars,1 heart,and mark as brainliest. Thanks

Answer:

Step-by-step explanation:

-2x+y

-2x2+-3

-4+-3

7

Answer:  -25/100 or -1/4

Sorry if its wrong, Happy To Help

Step-by-step explanation:

Answer: I can not see the picture

Step-by-step explanation:

can you show it?

Answer: d=c/4

Step-by-step explanation:

9514 1404 393

Answer:

  4x +y = -1

Step-by-step explanation:

The equation of the perpendicular line can be written by ...

The x- and y-coefficients in the given equation are 1 and -4, respectively. Since we want the leading coefficient positive, it is convenient to use 4 and 1 as the coefficients in the new equation. The constant can be found by substituting (x, y) = (-2, 7) to see what it is.

  4x +y = 4(-2) +7 = -1

The desired perpendicular line has an equation ...

  4x +y = -1

Answer:

$4.24

Step-by-step explanation:

100%-15%=85%

85/100x4.99=4.2415

4.2415 rounded off to nearest cent =4.24

Hope this helps! Thanks.

Step-by-step explanation:

false

0 can't he greater then any integer.

Answer:

area of triangle = 1/2×base×height

=1/2×20m×6m

= 20m×6m=120square metre