A fourth grade teacher gives homework every night in both mathematics and language arts. The time to complete the mathematics homework has a mean of 10 minutes and a standard deviation of 3 minutes. The time to complete the language arts assignment has a mean of 12 minutes and a standard deviation of 4 minutes. The time to complete the mathematics and the time to complete the language arts homework has a correlation rho = -0.75. The variance of the time to complete the entire homework assignment is

Answers

Answer 1

Answer:

4

Step-by-step explanation:

Given that:

X = time taken to complete mathematics homework

Y= time taken to complete language homework

Standard deviation of X ; SD(X) = 3

Standard deviation of Y ; SD(Y) = 4

rho = - 0.375

rho = Cov(X, Y) / SD(X) * SD(Y)

-0.375 = COV(X, Y) / 3 * 4

COV(X, Y) = 12 * - 0.375

COV(X,Y) = - 4.5

Variance(X, Y) = V(X, Y)

V(X, Y) = V(X) + V(Y) + 2COV(X,Y)

V(X) =SD(X)² = 3² = 9

V(Y) = SD(Y)² = 4² = 16

V(X,Y) = 9 + 16 + 2(-4.5)

V(X, Y) = 16

SD(X, Y) = sqrt(V(X, Y)) = sqrt(16) = 4

Hence, standard deviation to complete entire homework, SD(X, Y) = 4


Related Questions

What is 16% of 80?
PLEASE DO NOT SOLVE, I KNOW THE ANSWER IS 12.8. JUST WRITE A PROPORTION ON HOW YOU GET THE ANSWER

Answers

Answer:

12.8

Step-by-step explanation:

(16÷100)×80 = 12.8

To start, you need to move the decimal point over two places to the right, which gives you 0.16. You can then multiply 0.16 by 80, which gives you 12.8.

I need help in the answer it’s math

Answers

E

Step-by-step explanation:

lolkyuhgt5jjnnnnnnneeeee

Which trigonometric expression is to equal to the ratio 12/13 in the right triangle?

A. tan X
B. cos X
C. tan W
D. cos W

Answers

Answer:

[tex]\Huge\boxed{D}[/tex]

Step-by-step explanation:

Hello There!

To find the answer we want to find the trigonometric ratio for each answer choice

important note;

[tex]sin =\frac{opposite}{hypotenuse} \\\\cos=\frac{adjacent}{hypotenuse} \\\\tan=\frac{opposite}{adjacent}[/tex]

for A,

the opposite of angle X is  12 and the adjacent of angle x is 5

so [tex]tanX=\frac{12}{5}[/tex] therefore A is not the answer

for B,

the adjacent of angle x is 5 and the hypotenuse is 13

so [tex]cosX=\frac{5}{13}[/tex] therefore B is not the answer

for C,

the opposite of angle W is 5 and the adjacent of angle W is 12

so [tex]tanW=\frac{5}{12}[/tex] therefore C is not your answer

for D,

the adjacent of angle W is 12 and the hypotenuse is 13

so [tex]cosW=\frac{12}{13}[/tex] therefore D is your answer

Mrs. Vargas went to lunch, and the bill was $28 for the meal. How much will the tip be if she wants to leave a 15% tip?


Explain

Answers

Answer:

Step-by-step explanation:

Percent means per one hundred, so to leave a 15% tip

28(15/100)=$4.20

The tip will be $4.20

what is the measurement of GAB

Answers

6 I think...................

Step-by-step explanation:

option B 52 is the correct answer of this question.

plz mark my answer as brainlist plzzzz.hope this will be helpful to you ☺️.

Mark is putting a round fountain in his backyard. He decides to place bricks around the edge of the fountain. If the radius of the fountain is 1.5 feet, what is the length of the brick edge?

Answers

Answer: 9.42ft :)

Step-by-step explanation: Your Welcome!!!

What value of x satisfies this equation, x2−12=13?

Answers

Answer:x=5 and x=-5

Step-by-step explanation:

In the equation: y=3x, what is the 3 called?

Answers

3 is the Coefficient in the following expression.

Need help with the correct answer please! Thank you. Which two triangles are congruent by the SSS Theorem? I picked D but that is the wrong answer.

Answers

Answer:

B

Step-by-step explanation:

RQ=TV

QS=VU

RS=TU

While proving that 2 triangles are congruent you have to consider the same side for both triangles.

The mistake you made was that you presumed that since both have equal sides they are equal,

In a sense that is true but you have align it in the correct way, in option D) it shows RQ is equal to TU which is wrong, RQ is equal to VT, you have align it in a proper way.

B) ΔRQS ≅ ΔTVU here it is align perfectly to be matched

Happy to help :)

If you need any more help, you can ask me

Directions: Foil the following if the answer is not standard form then standardize it.
Equation: (x+4) (4x−5)

Answers

The answer to your question is 4x^2+11x-20
the answer to your question is
4x^2+11x-20
(the “^2” is the tiny 2 lol)

5y + 3y + 5 ≤ ‐2(2y + 4) ( pls show work)

Answers

Answer:

y<-13/12

Step-by-step explanation:

12y<-8-5

12y<-13

The area of a trapezoid is 60 square feet the bases of the trapezoid are 8 feet and 12 feet, what is the height?
6ft
4ft
3ft
15ft​

Answers

It is 6 feet. I hope this helps a little.

Rank the following in order from most precise to least precise.
1500 grams
8.43 inches
1580 meters
5.426 seconds

Answers

Answer:

1st most = 8.43 inches

2nd most = 5,426 Seconds

3rd most = 1580 meters

4th most = 1500 grams

Step-by-step explanation:

8.43 inches = 0.7025 feet is most precise as it rounded to 0.7 feet it wouldn't be precise enough.

5,426 Seconds =  01:30:26. hrs mins sec can be converted.

1580 meters = 1.58 km = 158000cm  hasn't been properly converted as zeros get lost.

1500 grams = 1.5kg hasn't been precisely converted as zeros get lost.

I need number 1 and 2 and 3 and 4 pleaseeeeer

Answers

Answer:

this is a test im not helping

Step-by-step explanation:

Angel uses 1/8 cup of sugar for 1/3 of a recipe. How much sugar is needed if Angel makes the entire recipe twice?

plz tell me the steps

Answers

Answer:

3/4 cups

Step-by-step explanation:

1/8 for 1/3 refipe

1/8 * 3 = 3/8

3/8 for 1 whole recipe

3/8 * 2 = 6/8 = 3/4

3/4 for 2 whole recipes

Why is this question stumping everyone i meet.

Answers

Answer:

i dont know anything about simplest radical form but this is the length 17.32051

Step-by-step explanation:

In a bowl there are 15 candy bars.

6 are Snickers
5 are Kit Kat
The rest of the candy bars are Milky Ways
If you eat a candy bar and then choose another candy bar, what is the probability that the first bar will be a Snickers and the second will be a Milky Way?

Answers

Answer:

The answer should be 10/27, good luck!

can you help me find the slope of these queastions?

Answers

Answer:

1. B

2. A

3. I

4. I

These should be correct

What is measure of the missing angle? HELP

Answers

(2x - 7) + ( x + 4) = 90°

2x + x - 7 + 4 = 90°

3x - 3 = 90°

3x = 90 + 3

3x = 93

x = 93/3

x = 31°

2x - 7

= (2 . 31) - 7

= 62 - 7

= 55°

x + 4

= 31 + 4

= 35°

#CMIIW

Need help.
Find the value of each variable.

Answers

It’s an isosceles triangle, so x would also equal 13, and now we just do the Pythagorean thrm

a^2+b^2=c^2

a=13 b=13

13^2+13^2= c^2

169+169= c^2

338= c^2 *square root both sides*

c= 18.38=y

In which step did Daniela make the first error?

Answers

you need to add an attachment
Add an attachment...

what is 1/10 (3n+50)=35?​

Answers

Answer:

100

Step-by-step explanation:

1/10(3n+50)=35

3n+50=35*10

3n+50=350

3n=350-50

3n=300

n=300/3

n=100

Derrick wants to calculate the interest he would earn from investing $400 into an account that earns 5.5% annual compound interest for 60 months. Which of the following formulas is set up correctly to help him do this?

Answers

Answer:

c

Step-by-step explanation:

The formula that should be set up correctly to help him do this should be considered as the [tex]400(1 + 5.5\%)^{60}[/tex]

Calculation of the formula:

Since

the invested amount is $400

The annual compound interest is 5.5%

And, the number of months should be 60

So here the formula that should be used should be [tex]400(1 + 5.5\%)^{60}[/tex]

Hence, The formula that should be set up correctly to help him do this should be considered as the [tex]400(1 + 5.5\%)^{60}[/tex]

Learn more about interest rate here: https://brainly.com/question/14191952

1) f(x)=(x - 3)(x - 5)
A f(x) = x2 - 8x+15
B. f(x) = x2 -15x-8
C. $(x) = x? - 8x-15

which is the equivalent?​

Answers

Answer:

Step-by-step explanation:

f(x)= (x - 3)(x - 5)

f(x) = x^2 - 5x - 3x + 15

f(x) = x^2 - 8x + 15

Answer is A

Kenya is trying to find matching socks. There are 4 red socks, 6 blue socks, and 2 white socks in her drawer. What is the probability that Kenya will pull out a blue sock, put it on, and then pull out another blue sock to put on?

Answers

Answer:

1/3 is the probaility

Step-by-step explanation:

since there are 3 different socks the answer would be 1/3

Answer:

The probability of her pulling of a blue sock the first time is 6 out of 12

The probability of her pulling out a blue sock the 2nd time would be 5 out of 11

10 POINTS PLEASE HURRY

Answers

3,14.81/2 = 127.17
,,,,,,,,,

Answer:

Since there are an infinite number of lines through the center, the circle has an infinite number of lines of symmetry. When the circle is folded over a line of symmetry, the parts of the circle on each side of the line match up. This means that the parts of the circle on each side of the line must have the same area.

Step-by-step explanation:

Can someone please solve this it's very important thank you

Answers

So basically you have the equation y=6/x-2 and as it shows you in the example on the bottom of the page, you plug in the X values for X and whatever you get will be the Y on the other side. For example the first one is already done for you so in the second one you take the next X which is -3 and plug it into your equation. Y=6/(-3)-2 and that would reduce to Y=6/-5 and you can either put that for your next answer or convert it into a decimal. (This example is for the second answer in the Y column)

Find the measures of the numbered angles in the kite.

Answers

Answer:

1 is 90

2 is 52

Step-by-step explanation:

1 is a right angle so its 90

for 2 angles in a triangle equal to 180

so 180-90-38 is equal to 52

You deposit 10,000 into a savings account that compounds quarterly. The account has an interest rate of 3.7%. What would be the value of the investment after 30 year

Answers

Answer:

30189.155

Step-by-step explanation:

Recall the compound interest formula :

A = P(1 + r/n)^nt

P = principal = 10000

r = rate = 3.7% = 0.037

n = quarterly = 4

t = 30

A = 10000(1 + 0.037/4)^30*4

A = 10000(1 + 0.00925) ^120

A = 10000(1.00925)^120

A = 10000 * 3.0189155

A = 30189.155

Use the number line below to determine which of the following answer choices has statements that are all true

Answers

Answer: the last one

Step-by-step explanation: B REPRESENTS

-2 ½ . POINT D REPRESENTS 1 ¾ .

1 ¾ is bigger than -2 ½

The answer choice that has the statement that is true about the number line can be seen in the first option.

What is a number line?

A number line is a pictorial representation of lines on a calibrated straight line that serves as a basis for expressing real numbers on a straight line.

We should equally note that:

The left-hand side is the negative x-axis and,The right-hand side is the positive x-axis.

From the given figures;

Point A lies to the negative axis direction on point scale 4 i.e -4Point D lies extremely to another point scale so we can say it is [tex]\mathbf{1 \dfrac{3}{4}}[/tex]Since 3/4 is roughly 0.75 = 1 + 0.75 = 1.75

Therefore, we can conclude that Point A represents -4, Point D represents  [tex]\mathbf{1 \dfrac{3}{4}}[/tex] and  [tex]\mathbf{1 \dfrac{3}{4}}[/tex] > -4.

Learn more about number line here:

https://brainly.com/question/25230781

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