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3 years ago

Please help me this is for 40 points !!!!

Mathematics

2 answers:

uranmaximum [27]3 years ago

8 0

Help you with what? There is no context. Send the text

nekit [7.7K]3 years ago

5 0

Answer:

what?

Step-by-step explanation:

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A true-false quiz with 10 questions was given to a statistics class. Following is the probability distribution for the score of

disa [49]

Answer:

$E(X)=\sum_{i=1}^n X_i P(X_i)$

And if we use the values obtained we got:

$E(X)=5*0.05 +6*0.15 +7*0.33 +8*0.28+ 9*0.12 +10*0.07=7.48$

For this case this value means that the expected score is about 7.48

Step-by-step explanation:

For this case we assume the following probability distribution:

X 5 6 7 8 9 10

P(X) 0.05 0.15 0.33 0.28 0.12 0.07

First we need to find the expected value (first moment) and the second moment in order to find the variance and then the standard deviation.

In order to calculate the expected value we can use the following formula:

$E(X)=\sum_{i=1}^n X_i P(X_i)$

And if we use the values obtained we got:

$E(X)=5*0.05 +6*0.15 +7*0.33 +8*0.28+ 9*0.12 +10*0.07=7.48$

For this case this value means that the expected score is about 7.48

In order to find the standard deviation we need to find first the second moment, given by :

$E(X^2)=\sum_{i=1}^n X^2_i P(X_i)$

And using the formula we got:

$E(X^2)=(5^2 *0.05)+(6^2 *0.15)+(7^2 *0.33)+(8^2 *0.28)+ (9^2 *0.12 +(10^2 *0.07))=57.46$

Then we can find the variance with the following formula:

$Var(X)=E(X^2)-[E(X)]^2 =57.46-(7.48)^2 =1.5096$

And then the standard deviation would be given by:

$Sd(X)=\sqrt{Var(X)}=\sqrt{1.5096}=1.229$

5 0

4 years ago

Read 2 more answers

Question 6 of 10

siniylev [52]

Answer:

You need to get a tutor!!!!!

Step-by-step explanation:

√

7. [c

2 = a

2 + b

2 − 2ab cos C.] (5 marks)

2. x

−4/3 +

16 = 1. [Verify that the point is on the curve. Find slope

dx = 12 (at that point)

and the tangent y + 8 = 12(x + 2). (5 marks)

Rearrange the equation to get it in intercept form, or solve y = 0 for x-intercept and x = 0

for y-intercept.] (5 marks)

3. One. [Show that g

(t) < 0 ∀t ∈ R, hence g is strictly decreasing. Show existence. Show

uniqueness.] (5 marks)

Comment: Graphical solution is also acceptable, but arguments must be rigorous.

4. 4π(9 − 2

√

6) or 16.4π or 51.54 cm3

. [V =

R 2π

R Rh

√

R2 − r

2 rdrdθ, R = 3, Rh =

√

Sketch domain. (5 marks)

V = 4π

R Rh

√

R2 − r

2 rdr, substitute R2 − r

2 = t

. (5 marks)

Evaluate integral V = −4π

√

R2−R2

R t

2dt.] (5 marks)

5. (a) (2,1,8). [Consider p~ − q~ = ~s − ~r.] (5 marks)

(b) p

3/5. [cosQ =

QP~ ·QR~

kQP~ k kQR~ k

.] (5 marks)

(j + 2k). [Vector projection = (QP~ · QRˆ )QRˆ .] (5 marks)

(d) 6

√

6 square units. [Vector area = QP~ × QR~ .] (5 marks)

(e) 7x + 2y − z = 8.

[Take normal n in the direction of vector area and n · (x − q).] (5 marks)

Comment: Parametric equation q + α(p − q) + β(r − q) is also acceptable.

(f) 14, 4, 2 on yz, xz and xy planes. [Take components of vector area.] (5 marks)

6. 1.625%. [A = πab ⇒ dA

A = da

a + db

. (5 marks)

Put a = 10, b = 16 and da = db = 0.1.] (5 marks)

7. 9/2. [Sketch domain: region inside the ellipse x

2 + 4y

2 = 9 and above the x-axis. (5 marks)

By change of order, I =

R 3

−3

R 1

√

9−x2

ydydx

3 0

2 years ago

Six friends share a 15 once bag of nuts equally between witch too whole numbers will each get

Bogdan [553]

Answer:

if you divide 15 by 6 you should get 2.5 as your answer

5 0

3 years ago

Read 2 more answers

How do you simplify 55/20

nasty-shy [4]

Find the greatest common factor. For this it would be 11/4

3 0

3 years ago

Read 2 more answers

Solve the following system. x2 + y 2= 25 2x + y = 10 The solution set

anzhelika [568]

Answer: {(5,0), (3,4)}

Step-by-step explanation:

You can apply the Substitution method:

- Solve for y from the second equation.

- Substitute into the first equation and solve for x.

Then:

$y=10-2x$

$x^2+y^2=25\\x^2+(10-2x)^2=25\\$

(Remember that: $(a\±b)^2=a^2\±2ab+b^2$ )

$x^2+(10^2-2(10)(2x)+(2x)^2)=25\\x^2+100-40x+4x^2=25\\5x^2-40x+75=0\\x^2-8x+15=0\\(x-5)(x-3)=0\\\\x=5\\x=3$

Substitute the values obtained into one of the original equation and solve for y:

$2(5)+y=10\\10+y=10\\y=0\\\\2(3)+y=10\\6+y=10\\y=4$

The solution set is: {(5,0), (3,4)}

8 0

3 years ago