Given that a random variable X is normally distributed with a mean of 2 and a variance of 4, find the value of x such that P(X < x)

The question is incomplete. Here is the complete question.

In a recent year, the socres for the reading portion of a test were normally distributed, with a mean of 23.3 and a standard deviation of 6.4. Complete parts (a) through (d) below.

(a) Find the probability that a randomly selected high school student who took the reading portion of the test has a score that is less than 18. (Round to 4 decimal places as needed.)

(b) Find a probability that a random selected high school student who took the reading portion of the test has a score that is between 19.9 and 26.7.

(c) Find a probability that a random selected high school student who took the reading portion of the test ahs a score that is more than 36.4.

(d) Identify any unusual events. Explain your reasoning.

Answer: (a) P(X<18) = 0.2033

              (b) P(19.9<X<26.7) = 0.4505

              (c) P(X>36.4) = 0.0202

               (d) Unusual event: P(X>36.4)

Step-by-step explanation: First, determine the z-score by calculating:

[tex]z = \frac{x-\mu}{\sigma}[/tex]

Then, use z-score table to determine the values.

(a) x = 18

[tex]z = \frac{18-23.3}{6.4}[/tex]

z = -0.83

P(X<18) = P(z< -0.83)

P(X<18) = 0.2033

(b) x=19.9 and x=26.7

[tex]z = \frac{19.9-23.3}{6.4}[/tex]

z = -0.67

[tex]z = \frac{26.7-23.3}{6.4}[/tex]

z = 0.53

P(19.9<X<26.7) = P(z<0.53) - P(z< -0.67)

P(19.9<X<26.7) = 0.7019 - 0.2514

P(19.9<X<26.7) = 0.4505

(c) x=36.4

[tex]z = \frac{36.4-23.3}{6.4}[/tex]

z = 2.05

P(X>36.4) = P(z>2.05) = 1 - P(z<2.05)

P(X>36.4) = 1 - 0.9798

P(X>36.4) = 0.0202

(d) Events are unusual if probability is less than 5% or 0.05. So, part (c) has an unusual event.

The probability will be:

(a) 0.2038

(b) 0.4046

(c) 0.0203

(d) Event in part (c) is unusual.

According to the question,

Let,

(a)

The z-score for X=18 will be:

→ [tex]z = \frac{X- \mu}{\sigma}[/tex]

      [tex]= \frac{18-23.3}{6.4}[/tex]

      [tex]= -0.828[/tex]

So,

The probability will be:

→ [tex]P(X<18) = P(z < -0.828)[/tex]

                     [tex]= 0.2038[/tex]

(b)

The z-score for X=19.9 will be:

→ [tex]z = \frac{X -\mu}{\sigma}[/tex]

     [tex]= \frac{19.9-23.3}{6.4}[/tex]

     [tex]= -0.531[/tex]

The z-score for X=26.7 will be:

→ [tex]z = \frac{X -\mu}{\sigma}[/tex]

      [tex]= \frac{26.7-23.3}{6.4}[/tex]

      [tex]= 0.531[/tex]

So,

The probability will be:

→ [tex]P(19.9 < X< 23.3) = P(-0.531 < z< 0.531)[/tex]

                                   [tex]= 0.4046[/tex]

(c)

The z-score for X=36.4 will be:

→ [tex]z = \frac{X -\mu}{\sigma}[/tex]

     [tex]= \frac{36.4-23.3}{6.4}[/tex]

     [tex]= 2.047[/tex]

So,

The probability will be:

→ [tex]P(X > 36.4 )= P(z > 2.047)[/tex]

                       [tex]= 0.0203[/tex]

(d)

Just because it's probability value is less than 0.05, so that the events is "part c" is unusual.

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Answer:

40.63

Step-by-step explanation:

31.25+9.38= 40.63

Hope this helps

Answer: 40.63

Look at the image for shown work.

Answer:

[tex]V_2=305.14\ \text{inch}^3[/tex]

Step-by-step explanation:

The volume of a gas in a container varies inversely as the pressure on the gas.

[tex]V\propto \dfrac{1}{P}\\\\V_1P_1=V_2P_2[/tex]

If V₁ = 356 inch³, P₁ = 6 pounds/in², P₂ = 7 pounds/in², V₂ = ?

So, using the above relation.

So,

[tex]V_2=\dfrac{V_1P_1}{P_2}\\\\V_2=\dfrac{356\times 6}{7}\\\\V_2=305.14\ \text{inch}^3[/tex]

So, the new volume is [tex]305.14\ \text{inch}^3[/tex].

Answer:

[tex] - 24 + 16i + 45i + 15 = 9 + 61i[/tex]

Answer:

work is pictured and shown

Answer:

5

Step-by-step explanation:

This shape is formed by two right triangles.

Let's start by the little one.

Let y be the third side.

Using the Pythagorian theorem we get:

y^2 = 6^2 + 3^2

y^2 = 36 + 9

y^2 = 45

y = 3√(5)

●●●●●●●●●●●●●●●●●●●●●●●●

Now let's focus on the second triangle. Let z be the third side.

The Pythagorian theorem:

6^2 + x^2 = z^2

Using the Pythagorian theorem on the big triangle :

[3√(5)]^2 + z^2 = (3+x)^2

45 + z^2 = 3x^2 + 6x + 9

36 +z^2 = 3x^2 +6x

So we have a system of equations.

36+ x^2 = z^2

36 +z^2 = 3x^2 +6x

We want to khow the value of x so we will eliminate z .

Add (36+x^2 -z^2 =0) to the second one.

36 + x^2-z^2+36+z^2 = 3x^2+6x

72 + x^2 = 3x^2 +6x

72 - 2x^2 -6x = 0

Multipy it by -1 to reduce the number of - signs

2x^2 + 6x -72 = 0

This is a quadratic equation

Let A be the discriminant

● a = 2

● b = 6

● c = -72

A = b^2-4ac

A = 36 -4*2*(-72) = 36 + 8*72 =612

So this equation has two solutions

The root square of 612 is approximatively 25.

● (-6-25)/4 = -31/4 = -7.75

● (-6+25)/4 = 19/4 = 4.75 wich is approximatively 5

A distance cannot be negative so x = 5

Answer:

The 99% confidence interval is  [tex]71.67 < \mu < 78.33[/tex]

Step-by-step explanation:

From the question we are told that

     The sample  size  is  [tex]n = 15[/tex]

      The  sample  mean is  [tex]\= x = 75[/tex]

        The  standard deviation is  [tex]s = 5[/tex]

 Given that confidence is  99%  then the level of significance is mathematically represented as

              [tex]\alpha = 100 - 99[/tex]

             [tex]\alpha = 1\%[/tex]

             [tex]\alpha = 0.01[/tex]

Next we obtain the critical values of  [tex]\frac{ \alpha }{2}[/tex] from the normal distribution table

   The  value is

                  [tex]Z_{\frac{ \alpha }{2} } = 2.58[/tex]

Generally the margin for error is mathematically represented as

            [tex]E = Z_{\frac{ \alpha }{2} } * \frac{ s}{ \sqrt{n} }[/tex]

=>         [tex]E = 2.58 * \frac{ 5}{ \sqrt{15} }[/tex]

=>         [tex]E = 3.3307[/tex]

   The  99% confidence interval is mathematically represented as

             [tex]\= x -E < \mu < \= x +E[/tex]

=>          [tex]75 - 3.3307 < \mu <75 + 3.3307[/tex]

=>          [tex]71.67 < \mu < 78.33[/tex]

Answer:

2+4+6+8

Step-by-step explanation:

We have the sum of 2n  where n runs from 1 to 4

n=1  2(1) = 2

n=2  2(2) = 4

n=3  2(3) = 6

n=4  2(4) = 8

The sum is add

2+4+6+8

(a) The average value of f(x) on the closed interval [0, π] is

[tex]\displaystyle\frac1{\pi-0}\int_0^\pi f(x)\,\mathrm dx = \frac1\pi\int_0^\pi(8\sin(x)-4\sin(2x))\,\mathrm dx = \boxed{\frac{16}\pi}[/tex]

(b) By the mean value theorem, there is some c in the open interval (0, π) such that f(c) = 16/π. Solve for c :

8 sin(c) - 4 sin(2c) = 16/π

8 sin(c) - 8 sin(c) cos(c) = 16/π

sin(c) - sin(c) cos(c) = 2/π

Use a calculator to solve this. You should get two solutions, c ≈ 1.2382 and c ≈ 2.8081.

Answer:

6720 in ^3

Step-by-step explanation:

Volume = length * width * height

            = 30*16*14

                =6720 in ^3

Answer:

C. $37.76

Step-by-step explanation:

30% of $49.95

=30/100×49.95

=$14.99

selling price = 49.95 -14.99

= $34.96

8% sales tax included

=8/100×34.96

=$2.80

new price= 34.96+2.80

=$37.76

Answer:

no of new computers sold : 8

no. of refurbished computer sold : 12

Step-by-step explanation:

Let the no. of new computers sold be x

let the no. of refurbished computers sold be y

Given

In March, the store sold 20 computers

x + y = 20

y = 20-x ----- equation 2

selling price of new computer = $500

selling price of x new computer = 500*x = 500x

selling price of refurbished computer = $200

selling price of y refurbished computer = 200*y = 200y

Total selling price of x new computer and y refurbished computers = 500x+200y

given that

total prioce of computer is $6400

thus

500x+200y = 6400

using y = 20-x  from equation 2

500x+200(20-x) = 6400

=> 500x+ 4000 - 200x = 6400

=> 300x = 6400 - 4000 = 2400

=> x = 2400/300 = 8

Thus,

no of new computers sold = 8

no. of refurbished computer sold = 20 -8 = 12

Answer:

Step-by-step explanation:

The first thing you want to do is to factor in any quadratic equation.

So, -10(x^2-25)

Now, we see this is a special case, whenever we see a equation in this case, x^2 - b^2, we factor it to this (x+b)(x-b)

So, -10(x+5)(x-5)

x = -5 and x = 5

Answer:

13/6

Step-by-step explanation:

We can use the slope formula

m = ( y2-y1)/(x2-x1)

   = (6 - -7)/(1 - -5)

   = ( 6+7)/ (1+ 5)

   = 13/6

Answer:

±7 sqrt(2) = x

Step-by-step explanation:

98 - x^2 = 0

Add x^2 to each side

98 =x^2

Take the square root of each side

±sqrt(98) = sqrt(x^2)

±sqrt(49*2) = x

±7 sqrt(2) = x

Answer:

[tex]\huge \boxed{{x = \pm 7\sqrt{2} }}[/tex]

Step-by-step explanation:

[tex]98-x^2 =0[/tex]

[tex]\sf Add \ x^2 \ to \ both \ sides.[/tex]

[tex]98=x^2[/tex]

[tex]\sf Take \ the \ square \ root \ of \ both \ sides.[/tex]

[tex]\pm \sqrt{98} =x[/tex]

[tex]\sf Simplify \ radical.[/tex]

[tex]\pm \sqrt{49} \sqrt{2} =x[/tex]

[tex]\pm 7\sqrt{2} =x[/tex]

[tex]\sf Switch \ sides.[/tex]

[tex]x= \pm 7\sqrt{2}[/tex]

Answer: The cube with side length of 12cm is alone in one plate, the other 3 cubes are in the other plate.

Step-by-step explanation:

We have 4 cubes with side lengths of:

6cm, 8cm, 10cm and 12cm.

Now, some things you need to know:

If we want a scale to be balanced, then the mass in both plates must be the same.

The volume of a cube of side length L is:

V = L^3

And the mass of an object of density D, and volume V is:

M = D*V.

As all the cubes are of the same material, all of them have the same density, so the fact that we do not know the value of D actually does not matter here.

Then we want to forms two groups of cubes in such a way that the total volume in each plate is the same (or about the same), the volumes of the cubes are:

Cube of 6cm:

V = (6cm)^3 = 216cm^3

Cube of 8cm:

V = (8cm)^3 = 512cm^3

Cube of 10cm:

V = (10cm)^3 = 1000cm^3

cube of 12cm

V = (12cm)^3 =  1728cm^3

First, if we add the volumes of the first two cubes, we have:

V1 = 216cm^3 + 512cm^3 = 728cm^3

Now we can see that we add 1000cm^3 the volume will be equal to the volume of the larger cube, so here we can also add the cube with side length of 10cm

Then the volume of the 3 smaller cubes together is:

V1 = 216cm^3 + 512cm^3 + 1000cm^3 = 1728cm^3.

Then, if we want to have the same volume in each plate, then we need to have the 3 smaller cubes in one plate, and the larger cube in the other plate.

Answer:

8 pounds of cheaper candy,

17.5 pounds of expensive candy

Step-by-step explanation:

Let's define some variables. Let's say the amount of pounds of candy that sells for $2.20/lb is x, and the $7.30 is y. Now we can write some equations!

x + y = 25.5

[tex]\frac{2.2x + 7.3y}{25.5} = 5.7[/tex]

We can start substitution. We can say that x = 25.5 - y. Plugging this into our second equation, we get:

y = 17.5

Plugging this in, we find that:

x = 8.

Answer:

C = 2pie(r)

r= d/2= 13/2= 6.5

C = 2*3.14*6.5

C= 41

Step-by-step explanation:

Answer:

Reserve rate = 9%

Step-by-step explanation:

Reserve ratio/rate is the percentage of deposits which commercial banks are required to keep as cash, as directed by the central banks.

first, let us calculate the reserve amount as follows:

Reserve = Deposit - (free amount to lend out)

Reserve = 28,000 - 25,480 = $2,520

[tex]Reserve\ rate = \frac{Reserves}{Deposits} \times100\\Reserve\ rate = \frac{2520}{28000} \times100\\=\frac{252000}{28000} =9\%[/tex]

Therefore the reserve rate = 9%

Hey  There!

Answer:

Step-by-step explanation:

HCF

If HCF is  ''9'' that means that ''9'' is the divisible of two numbers.

So 18 and 19 can be divided by 9 and that's the highest divisible for both factors.

And always remeber the answer is a ''Prime factor.''

LCM

If LCM is ''3'' that means ''3'' is the lowest common multiple out of  two numbers.

Hope this helps!

Have a nice Day!:)

Answer:

∠A and ∠G is the pair of vertical angles.

Step-by-step explanation:

From the figure attached,

Two lines 'm' and 'n' are two parallel lines. These lines intersect a horizontal line 'l'.

Since, "Pair of opposite angles formed at the point of intersection are the vertical angles and equal in measure."

Therefore, Opposite angles ∠A ≅ ∠G, ∠B ≅ ∠H, ∠C ≅ ∠E and ∠D ≅ ∠F are the vertical angles.

From the given options,

∠A and ∠G is the pair representing the pair of vertical angles and thus congruent.

Answer:

a

Step-by-step explanation:

Answer:

Multiply/divide both sides by the same non-zero constant

Step-by-step explanation:

5x = 20

Divide each side by 5

5x/5 = 20/5

x = 4

To obtain (B) from (A) "Multiply/divide both sides by the same non-zero constant"

Given the equations :

To obtain the value ; x = 4 from A

Here, the constant value which can be used is 5 in other to isolate 'x'

5x/5 = 20/5

x = 4

Therefore, to obtain (B) from (A) "Multiply/divide both sides by the same non-zero constant"

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Answer:

b ≈ 9.2

Step-by-step explanation:

Using Pythagoras' identity in the right triangle.

The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is

b² = a² + c² = 6² +7² = 36 + 49 = 85 ( take the square root of both sides )

b = [tex]\sqrt{85}[/tex] ≈ 9.2 ( to the nearest tenth )

Answer:

9.22

Step-by-step explanation:

Since it's a 90° triangle [tex]c^{2} =a^{2} +b^{2}[/tex].

In this example they labeled the hypotenuse as b instead of c are equation is still the same just put the correct variables in the right places.

[tex]b = \sqrt{6^{2} +7^{2} }[/tex]

b = 9.22

Answer:

106.68 centimeters

Step-by-step explanation:

40.64 cm/16 in = x cm/42 in

Cross multiplying, we get:

16x = 40.64(42)

16x = 1706.88

x = 106.68 centimeters

Answer:

[tex]g(x) = 0.5^{(x+3)}[/tex]

Step-by-step explanation:

Assuming f(x) = [tex]0.5^{x}[/tex] is a correct interpretation of f(x),

the way to translate three units to the left is to change x to x+3.  This gives our answer:   [tex]g(x) = 0.5^{(x+3)}[/tex]

Answer:

B. g(x) = (1/2)⁽ˣ⁺³⁾

Hope this helps!

Step-by-step explanation:

Answer:

x and y can have many values

Step-by-step explanation:

-24x - 12y = -16

Then: 24x + 12y = 16

We know: 6x + 3y = 4

X and Y can have a lot of valoues.

6x + 3y = 4

3 ( 2x + y) = 4

2x + y= 4/3

2x+y= 1.333...

Answer:

The area of ΔABC= 6.667 square units

Step-by-step explanation:

ΔABC is similar to ΔMNO.

The scale factor from ΔMNO to ΔABC is 3∕2

the area of ΔMNO is 10 square units,

The area of ΔABC/the area of ΔMNO

= 2/3

The area of ΔABC/10= 2/3

The area of ΔABC= 2/3 * 10

The area of ΔABC= 20/3

The area of ΔABC= 6 2/3

The area of ΔABC= 6.667 square units

Answer:

22.5 square units

Step-by-step explanation:

i multiplied 10 by 2 to get 20 and went with the closest answer and got it right.

i dont know how to do math but i guess it worked

Answer:

D) 9 cm

Step-by-step explanation:

EDGE 2020

(D) 9 cm.

Therefore, the correct answer is (D) 9 cm.

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Answer:

3^x( 2-3^x)

Step-by-step explanation:

f(x) = 3^x and g(x) = 3^2x - 3^x

h(x) = f(x) - g(x)

       3^x - ( 3^2x - 3^x)

Distribute the minus sign

         3^x - 3^2x + 3^x

     2 * 3^x - 3 ^ 2x

Rewriting

We know that 3^2x = 3^x * 3^x

2 * 3^x - 3^x* 3^x

Factoring out 3^x

3^x( 2-3^x)