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
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
I'm sorry for asking so many math questions, I just need alot of help
Answer:
20 = √3/2hypo
20×2=√3 hypo
40=√3 hypo
hypo =23
23² = 20² + x²
529= 400+x²
x²= 529-400
x²=129
x= 12.8
Nadia's class took a math test. The median score on the test was 72% and the mean of the test scores was 72%.
What does this tell you about the data set?
The data shows causation.
The data is accurate.
The data is symmetrical.
Answer:
C, or "The data is symmetrically"
Step-by-step explanation:
This is because when having both the median and the mean the same, this means their is a perfectly symmetrical distribution of data. Making both the mean and median the same.
HELP ME PLEASE!!,I WILL GIVE BRAINLIEST!!I PROMISE!!:)
four ways on how save water
Edward has $20,000 in a savings account that earns 13% interest per year. The interest is not compounded.How much interest will he earn in 1 year?
Use the formula i = prt, where i is the interest earned, p is the principal (starting amount), r is the interest rate expressed as a decimal, and t is the time in years.
$
Answer:
22,600
Step-by-step explanation:
Natalie lost her job through no fault of her own. She had worked there for two years and the last year she earned $27,500. She has applied for unemployment insurance. What will her weekly benefit be?
Answer:
it should be around $527
Step-by-step explanation:
Answer:
550
Step-by-step explanation:
426 per week up to 26 weeks
The distance a train travels between 2 cities is 540 miles. The train travels at a speed of 80 miles per hour. Matt set up these rates to find the time it took the train to travel between the 2 cities.
Answer:
it takes 6 hours 40 minutes
Answer: 6.75 hours
Step-by-step explanation:
540%80=6.75
24% of 40
I need it worked out pls thank uuu:)
Step-by-step explanation:
24% is the same as 6/25
[tex] \frac{6}{25} \times 40 \\ = \frac{48}{5} = 9.6[/tex]
Answer:
9.6
Step-by-step explanation:
24% of 40 = 0.24 × 40 = 9.6
Simplify: 3x + 6y - (4x - 2y)
Answer:
-x + 8y
Step-by-step explanation:
Can someone help me with Tuesday’s question??
Answer:
B
Step-by-step explanation:
The sales tax rate in Connecticut is 6.35%. Megan wants to buy a jacket with a $45.00 price tag. She has a gift card to the store she wants to use. What amount needs to be on the gift card for Megan to be able to buy the jacket using only the gift card?
Answer:
$47.86
Step-by-step explanation:
A tax is a compulsory amount levied by the government or an agency of the government on goods and services
Taxes increases the price of goods and services. Thus, the amount paid would increase by the tax rate
Amount that needs to be on the gift card = amount of tax + price of the jacket
Price of the jacket = $45
Amount of tax = percentage tax rate x price of the jacket
0.0635 x $45 = $2.86
$45 + $2.86 = $47.86
Natalie is playing the Integer Game and only shows you the four cards shown below. She tells you that the rest of her cards have the same values on them and match one of these four cards.
Missing part of question
(a) If all matching cards will increase her score by 18, what are the matching cards
(b) If all matching cards will decrease her score by 12, what are the matching cards
See attachment for cards
Answer:
(a) 9 card number 2 or 6 card number 3
(b) 6 card number -6
Step-by-step explanation:
Given
The number on the cards are: 2, 3, -6 and 4
Solving (a): An increment of 18
From the card numbers attached, there are 3 positive numbers and 1 negative number
If any of the card numbers is to increase her score, then the card number must be positive. So, we have: card numbers 2, 3 and 4 that fit in this category.
Next, for a card number to give an increment of 18; the card number must be a factor of 18.
So, we have:
[tex]\frac{18}{2} = 9[/tex]
[tex]\frac{18}{3} = 6[/tex]
[tex]\frac{18}{4} = 4.5[/tex]
Only 2 and 3 are factors of 18.
So, Natalie cards are: 9 card number 2 or 6 card number 3
Solving (b): A decrement of 12
If any of the card numbers is to decrease her score, then the card number must be negative. So, we have: card -6 that fit in this category.
Next, is to check if -12 is divisible by -6 (-12 means decrement of 12)
So, we have:
[tex]\frac{-12}{-6} = 2[/tex]
So, Natalie cards are: 6 card number -6
HELPPPPPPPPPPPPPPPPPPPPPPPPPPPPP
A population of 470 animals decreases at an annual rate of 12%.
a.f(x)=470(1.88)x
b.f(x)=470(0.12)x
c.f(x)=470(0.88)x
d.f(x)=470(1.12)x
Answer:
C. f(x) = 470(0.88)ˣStep-by-step explanation:
Initial number = 470Decrease rate = 12% ⇒ 100% - 12% = 88% ⇒ 0.88 timesRequired equation:
f(x) = 470(0.88)ˣCorrect choice is C
A and B are independent events. Find P(A and B). P(A)=1/5, P(B)=3/7
Answer:
Step-by-step explanation:
plz help meh (ASAP) question below
Answer:
It's D I believe.
Step-by-step explanation:
I had this question before.. hopefully this helps
PLZ HELP RN ILL MARK YOU BRAINLIST IF ITS RIGHT PLZZZ IM DESPERATE
Answer:
w = -0.5
Step-by-step explanation:
Divide the entire equation by -6.8 to cancel it out and get your "w" variable alone.
w = -0.5
Answer:
-0.5
Step-by-step explanation:
divide 3.4/-6.8= -0.5
The shape of a patio is triangle without hight of 8 ft and base of 17 ft what is the cost of out door carpeting to cover the patio of the carpeting costs 6.50 per ft
Answer:
$442
Step-by-step explanation:
Given :
Height of patio, h = 8ft
Base of patio = 17 ft
Cost of carpeting = $6.50 per ft²
Area of triangular patio :
Area = 1/2 * base * height
Area = 0.5 * 17 * 8
Area of patio = 4 * 17
Area of patio = 68 ft²
Cost of carpeting :
Area of patio * contains st per ft²
68 * 6.50
= $442
Please Help me!!!
The question is:
Which graph shows the solution to y > x – 8?
Answer:
the answer is B
Step-by-step explanation:
In the following equation, which number is the slope (rate of change) and which is the y-intercept?
y = 32 - 4
Slope:
Y-Intercept:
Answer: Slope: 3z
Y intercept: -4
Step-by-step explanation:
could someone pls help me with this math problem?
Is negative 40 greater than 12
Answer:
No, 12 is greater than -40
Step-by-step explanation:
Answer: I think your question is: Is negative forty greater than positive 12. It is not greater. Even if it was negative 40 and negative 12 it still would not be greater. Hope this helps :)
Step-by-step explanation:
If y=2x and 3x – 3y = 2, then x
Answer:
x = - 2/3
Step-by-step explanation:
2x = y
3x - 6x = 2
- 3x = 2
- 3x ÷ - 3 = 2 ÷ - 3
x = 2 ÷ - 3
x = - 2/3
A circle with its dimensions, in centimeters (cm) is shown.
5 cm
What is the circumference, in centimeters, of the circle? Use 3.14 for. Round your answer to the nearest tenth
ANSWET FOR BRAINLIEST NOW
Step-by-step explanation:
add the radii to get the diameter then multipy by pi
10 (3.14) =31.4
Consider the following pair of equations:
-X - y = -5
y = x + 1
If the two equations are graphed, at what point do the
lines representing the two equations intersect? (4 points)
O (-2,3)
O (3,-2)
O (3, 2)
(23)
HELP ASAP
Answer:
Yeah i don't get it i have the same problem
Answer:
It is not (−2,3).
Step-by-step explanation:
Work out the value of x.
PLZ HELP ME WITH THIS, I'VE BEEN STUCK ON THIS FOR A WHILE.
You sell large and small pictures at a fair. You sell a total of 16 pictures and made a total of $350. If large pictures sell for $25 and small pictures sell for $20. How many of each did you sell?
Answer:
it is blink
Step-by-step explanation:
vgftr
Change 22 metres per second to a speed in kilometres per hour.
Show your working clearly.
Answer:
79.2 km/hour
Step-by-step explanation:
1 m/sec= 3.6 km/hour 22m/sec= ? so just multiply 22 m/sec by 3.6 km/hour then the answer will be :- 79.2 km/hour
In a family,the ages of children arranged from the youngest to the oldest are 2,6,y,14 and z.if the sequence of the ages is in an arithmetic progressions what is the ratio z:y
Answer:
9/5
Step-by-step explanation:
The common difference = 6 - 2 = 4
The age after 6 is 6 + 4 = 10 = y
The age after 14 is 14 + 4 = 18 = z
z/ y = 18/10 = 9/5
A company manufactures computers. Function N represents the number of components that a new employee can assemble per day. Function E represents the number of components that an experienced employee can assemble per day. In both functions, t represents the number of hours worked in one day.
N(t)=50t/t+4
E(t)= 70t/t+3
Which function describes the difference of the number of components assembled per day by the experienced and new employees?
A. D(t)= 10t(2t+13)/t+3
B. D(t)= 10t(2t+13)/ (t+4)(t+3)
C. D(t)= 10t(2t-13)/t+4
D. D(t)=10t(2t-13)/ (t+4)(t+3)
The difference of the number of components assembled per day by the experienced and new Employees is : D(t)= 10t(2t+13)/ (t+4)(t+3)
Here we perform subtraction :
D(t) = N(t) - E(t)
N(t) = 50t / (t+4)
E(t) = 70t / (t+3)
The difference :
D(t) = E(t) - N(t)
D(t) = [70t / (t+3)] - [50t / (t+4)]
The L.C.M of (t+3) and (t+4) is (t+3)(t+4)
[70t(t+4)] - [50t(t+3)] / (t+3)(t+4)
70t² + 280t - [50t² + 150t] / (t+3)(t+4)
[70t² + 280t - 50t² - 150t] / (t+3)(t+4)
20t² + 130t / (t+3)(t+4)
D(t) = 10t(2t + 13) / (t+3)(t+4)
The difference of the number of components assembled is : D(t)= 10t(2t+13)/ (t+4)(t+3)
Learn more : https://brainly.com/question/1166214
Answer:b
Step-by-step explanation:
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