For a discrete random variable that takes a value of 8 with probability .75 and a value of -4 with probability of .25, what is the expected value and what is the variance

Answers

Answer 1

Answer:

5.20

Step-by-step explanation:

X : ______ 8 ____ - 4

P(X) : ___ 0.75 __ 0.25

The expected mean E(x) :

E(x) = ΣX / n

n = sample size = 2

E(x) = (8*0.75) + (-4*0.25)

E(x) = 6 - 1

E(x) = 5

The standard deviation : sqrt(Var(x))

Var(x) = Σx²p(x) - E(x)²

Var(x) = (8^2 * 0.75) + (-4^2 * 0.25)) - 5^2

Var(x) = ((64 * 0.75) + (16* 0.25)) - 25

Var(x) = (48 + 4) - 25

Var(X) = 27

Standard deviation = sqrt(27)

Standard deviation (x) = 5.1961524

Standard deviation = 5.20


Related Questions

Farmer Bill sold potatoes at the farm market. He sold a quarter to the first person, 4/9 of what was left to the second person, and the third buyer bought 4/5 of what was left and the last 10 lb. How many pounds of potatoes did farmer Bill sell?

Answers

Answer:

Farmer Bill sold 120 lb of potatoes

Step-by-step explanation:

Suppose farmer Bill had x lb of potatoes. He sold a quarter to the first person. A quarter is written as (1/4)x. After that, Bill had x-(1/4)x = (3/4)x.

Then he sold 4/9 of what was left to the second person, thus it was left 1-4/9=5/9 of the remaining potatoes. Multiplying both factors:

[tex]\frac{5}{9}*\frac{3}{4}x=\frac{5}{12}x[/tex]

This is the remaining portion of the potatoes.

Finally, he sold 4/5 of it and the last 10 lb. This means 1 - 4/5 = 1/5 of the remaining is equivalent to 10 lb:

[tex]\frac{1}{5}*\frac{5}{12}x=\frac{1}{12}x[/tex]

Thus:

[tex]\frac{1}{12}x=10[/tex]

x = 120 lb

Farmer Bill sold 120 lb of potatoes

The Farmer will sold 120 lb of potatoes.

Let us consider that farmer have x lb of potatoes.

He sold a quarter to the first person, that is  [tex]\frac{x}{4}[/tex]

Potatoes left,[tex]=x-\frac{x}{4} =\frac{3x}{4}[/tex]

4/9 of what was left to the second person,

 Potatoes sell to second person is, [tex]\frac{3x}{4} *\frac{4}{9} =\frac{x}{3}[/tex]

the third buyer bought 4/5 of what was left

       that is,          [tex]\frac{4}{5}*(\frac{3x}{4} -\frac{x}{3} ) =\frac{x}{3}[/tex]

Potatoes left [tex]=\frac{5x}{12} -\frac{x}{3} =\frac{x}{12}[/tex]

Since, Potatoes left = 10 lb

So,   [tex]\frac{x}{12} =10\\\\x=12*10=120[/tex]

Thus, The Farmer will sold 120 lb of potatoes.

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Gabriel lives and works in Michigan, which has a flat state income tax of
4.25%. If his annual salary is $69,255 and he gets paid once a month, how
much is withheld from his gross income for state income tax each pay
period?

Answers

Answer:4,050

Step-by-step explanation:

Withholding Rate: 4.25% | Personal Exemption: $4,400 | 2019 Michigan Income Tax Withholding Tables. Withholding Rate: 4.25% | Personal Exemption: $4,050 | 2019 Michigan Income Tax Withholding Tables.

If an orca is 200 m below the surface of the water and then swims up and jumps 5 m in the air, what is the total distance it traveled?

Answers

Answer:

Total distanced traveled = 205 m

Step-by-step explanation:

200 m+5 m=205 m

pls help asap no trolls!!

Answers

Answer:

10

Step-by-step explanation:13+4>а>13-4

a>9

Ellen drove 357.3 miles. For each gallon of gas, the car can travel 21 miles. Select a reasonable estimate of the number of gallons of gas Ellen used. Mark all that apply.

Answers

Take 357.3 miles and divide by 21 gal/mile to get a final answer of 17 gallons used during the trip

Question
-8 – (-3) =

Answers

Answer:

-5

Step-by-step explanation:

-8 - -3 basically forget about the - just do the question 8 - 3 then u get 5 then add the - sign

Answer:

Step-by-step explanation:

-5

-8 -(-3)=

-8+3=

-5

Solve the equation. m + (–4) = –9 5 36 –5 –13

Answers

4m + 9 + 5m – 12 = 42. A. m = 5 B. m = 4 C. m = –5 D. m = -4

Which situation can be represented by the equation y=74x?

Answers

What do you "mean"?

If the scale is 3 inches = 4 kilometers. What is the amount of inches in 5 kilometers?

A 3.75 inches
B 3.75 kilometers
C 6.333.... inches
D 6.333....Kilometers ​

Answers

Answer:

3.75 inches is the correct answer..

Answer:

A. 3.75 inches

Step-by-step explanation:

The question is asking for the amount of inches not kilometers, so options B and D are automatically incorrect. I took the three inches and divided it by the four kilometers to kind inches per kilometer. The times the inches by five to get the correct answer;

3 inches = 4 kilometers

3 / 4 = 0.75

0.75 = 1 kilometer

0.75 x 5 = 3.75

3.75 inches = 5 kilometers

I hope this helps!

find the rate of travel for a fishing boat with a speed of 10 miles per hour moving Downstream with a current of 5 miles per hour ​

Answers

Answer:

36 miles (b+C) (3)of rate

Which decimal is greater than 0.15 and less than 0.7?
A. 0.81
B. 0.56
C. 0.76
D. 0.005​

Answers

Answer:

B. 0.56

Step-by-step explanation:

A. 0.81  > 0.7

B. 0.56  < 0.7 & 0.56 > 0.15

C. 0.76  > 0.7

D. 0.005​ < 0.15

15x+98=105 What is the value of x and please show your work. :) ​

Answers

Answer:

15x+98=105

      -98    -98

15x=7

/15    /15

x=7/15

Step-by-step explanation:

x=7/15


[tex](2x {}^{4} - 18x ^{2} + 3x - 4) \div (x ^{3} - 3x {}^{2} - 2)[/tex]

Answers

Answer:

(2x⁴-18x²+3x-4) = (2x+6)(x³-3x²-2) + (7x+8)  .... remainder  7x+8

Step-by-step explanation:

(2x⁴-18x²+3x-4) = (2x+6)(x³-3x²-2) + (7x+8) .... remainder  7x+8

Use long division method

A frog jumps 9 3/5 feet in the span of 2 2/3 seconds. Express as a complex fraction and then find the unit rate, in feet per second, that the frog is moving at. Express any improper fractions as mixed numbers.

Answers

Answer:

3 3/5 feet per seconds

Step-by-step explanation:

If a frog jumps 9 3/5 feet in the span of 2 2/3 second, we want to calculate the number of feet it can jump in one seconds.

Since it jumps 9 3/5 feet in the span of 2 2/3 second, we can express this as:

9 3/5 feet  = 2 seconds ... 1

The number of feet per seconds will be expressed as:

x = 1secs.... 2

Divide equation 1 by 2 as shown:

9 3/5 ÷ x = 2 2/3 ÷ 1

48/5x = 8/3

Cross multiply

5x * 8 = 48 * 3

40x = 144

10x = 36

5x = 18

x = 18/5

Express as a mixed fraction:

18/5 = 3 3/5ft/secs

Hence the frog is moving at 3 3/5 feet per seconds

Solve (9 - 3 x 2)^2 someone help me please im failing

Answers

Answer:

9

Step-by-step explanation:

Using PEMDAS, we do what inside the parentheses first.

Multiplication before subtraction:

9-6 = 3.

Finally, 3^2 = 9

Pended for the parenthesis:
9-6 = 3
3^2 = 3*3
The answer is 9

What is the simplified form of
72x16/50x36 ? assume x ≠ 0

Answers

Answer:

Option A

Step-by-step explanation:

[tex]\sqrt{\frac{72x^{16} }{50x^{36} } } = \sqrt{\frac{36x^{16} }{25x^{36} } } = \frac{\sqrt{36x^{16} } }{\sqrt{25x^{36} } } = \frac{\sqrt{36} \times \sqrt{x^{16} } }{\sqrt{25} \times \sqrt{x^{36} } } = \frac{6x^{8} }{5x^{18} } = \frac{6}{5} \times x^{8-18} =\frac{6}{5} \times x^{-10} = \frac{6}{5x^{10} }[/tex]

Is this the Right answer?

Answers

Answer:

yes i think it is

Step-by-step explanation:

checked each of them

given H(x)=4(x+3), which of the following is the value of H(-2)?

Answers

Answer:

H(-2)=4

Step-by-step explanation:

H(x)=4(x+3)

Let x =-2

H(-2)=4(-2+3)

      =4(1)

     = 4

Pete walks 2 miles in an hour. At this rate how many miles can Pete walk in 4 hours

Answers

Answer:

8 miles

Step-by-step explanation:

2 miles= an hour

4 miles= two hours

6 miles= three hours

8 miles = four hours

Answer:

8

Step-by-step explanation:

Use Pete's walking speed: 2 miles per hour × 4 hours = 8 miles.

The two triangles shown are congruent: AFHG=AJKL. Based on this information,
which of the following is a true statement?
A) HELL
B) JK= FG
OC) GEL
D

Answers

Answer is c in the photo
the correct answer would be C. also you’re welcome

Find the midpoint of points A(-8, 2) and B(-5, 10)

Answers

Answer:

-40×20

= -40/20

= -2

Step-by-step explanation:

!! PLEASE help !

Using two or more complete sentences, describe how you can find a vector parallel to b (-2,3) .

Answers

Any vector that points in the same or opposite direction would be parallel. So you can just scale (-2, 3) by any real number t to get the vector (-2t, 3t ).

For example, if t = -1, you get the vector (2, -3); if t = 2, you get (-4, 6).

FREE BRAINLIEST
Write an equation in point slope form for the line that passes through each point with the given slope.
(1,4), m=6

Answers

Answer:

y = 6x -2

Step-by-step explanation:

Answer:

y = 6x - 2

Step-by-step explanation:

pass (1,4)

y = mx + b

b = y - mx = 4 - 6 x 1 = -2

y = 6x - 2

What is 8 2/5 minus 5/8

Answers

Answer: 7.775 as a decimal, as a fraction, 311/40.

Step-by-step explanation:

Answer:

im 95%ly sure itz just 8

Step-by-step explanation:

How do you use long division to show the work?

Answers

Answer: 83.2/26= 3.2  

90. 54/18= 93

Step-by-step explanation: Divide the tens column dividend: by the divisor

Multiply the divisor by the quotient in the tens place column.

Subtract the product from the divisor.

Bring down the dividend in the ones column and repeat.

dividend: can be divided by another number)

divisor: Number that divides into another without a remainder.

You need to make 13 servings of fried fish. Each serving takes 7.5 ounces of flour. How many ounces of flour do you need?

Answers

Answer:

77,5

Step-by-step explanation:

13

. 75

_____

65

71

_____

77,5

1- is -12.17 a integer?
2- 5/5 an integer?
3- 485.84 an integer?
4 - -16/13 an integer?

Answers

Answers:

No, it is not an integer due to the decimal portion 0.17; integers are either positive or negative whole numbers. Zero is included as well.Yes it is an integer because 5/5 = 1 which has no decimal or fractional parts.No, it is not an integer for similar reasoning as problem 1. The 0.84 decimal portion is why we don't have an integer.No, it is not an integer because -16/13 = -1.2308 approximately, and we don't have a negative whole number here.

giving branliest, 7th grade math

Answers

Answer:

1/3

Step-by-step explanation:

Total number of outcomes = 3

Possible outcomes = 1

probability = possible outcomes/ total number of outcomes = 1/3

HOPE THIS HELPS YOU

Answer:

1/3

............................

The expression x3(x−y)7−y3(x−y)7 can be rewritten as (x−y)m(x2+y2+nxy). What is the value of m ?

Answers

Answer:

m = 8

Step-by-step explanation:

Given the expression:

x³(x−y)⁷−y³(x−y)⁷

This can also be written as (x³-y³)(x-y)⁷

(x³-y³)(x-y)⁷=  (x-y)⁷ (x³-y³)

Expand  (x³-y³)

x³-y³ = (x-y)(x²+xy+y²)

Substitute back into the original expression:

(x-y)⁷ (x³-y³) = (x-y)⁷(x-y)(x²+xy+y²)

(x-y)⁷ (x³-y³) = (x-y)⁸(x²+xy+y²)

(x-y)⁷ (x³-y³) = (x-y)⁸(x²+y²+xy)

Comparing the result with (x−y)^m(x^2+y^2+nxy).

(x-y)⁸ = (x-y)^m

m = 8

Also:

nxy = xy

n = xy/xy

n = 1

Hence the value of m is 8

The value of m is 8

The expression is given as:

[tex]x^3(x-y)^7-y^3(x-y)^7[/tex]

Factor out (x - y)^7 in the above expression

[tex]x^3(x-y)^7-y^3(x-y)^7 = (x^3 - y^3)(x -y)^7[/tex]

Expand out (x^3 - y^3) as the difference of two cubes

[tex]x^3(x-y)^7-y^3(x-y)^7 = (x-y)(x\²+xy+y\²)(x -y)^7[/tex]

Combine the common factors

[tex]x^3(x-y)^7-y^3(x-y)^7 = (x\²+xy+y\²)(x -y)^8[/tex]

Rewrite the expression as:

[tex]x^3(x-y)^7-y^3(x-y)^7 = (x -y)^8(x\²+xy+y\²)[/tex]

The expression format is given as:

[tex](x-y)^m(x^2+y2^+nxy)[/tex]

So, we have:

[tex](x-y)^m(x^2+y2^+nxy) = (x -y)^8(x\²+xy+y\²)[/tex]

By comparison, we have:

[tex]m = 8[/tex]

Hence, the value of m is 8

Read more about expressions at:

https://brainly.com/question/4344214

Solve.
X = -7
4x - 4y = 12
(x,y)

Answers

Answer:

(-7, -10)

[tex]x=-7\\y=-10[/tex]

Step-by-step explanation:

[tex]4x-4y=12[/tex]

Substitute x for -7.

[tex]4(-7)-4y=12[/tex]

Multiply 4 by -7.

[tex]-28-4y=12[/tex]

Add 28 on both sides.

[tex]-4y=40[/tex]

Divide -4 on both sides.

[tex]y=-10[/tex]

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