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Drupady [299]
3 years ago
13

On a recent quiz, the class mean was 70 with a standard deviation of 2.1. Calculate the z-score (to 4 decimal places) for a pers

on who received score of 76.
Mathematics
1 answer:
Igoryamba3 years ago
5 0
The equation to find a z score is (x- mean)/(standard deviation)

So, in this case the equation would be
(76-70)/(2.1)

For,
X=76
Mean=70
Standard Deviation= 2.1

After solving we find that the z score equals 2.85714

or

2.8571

You might be interested in
What are the methods of substitution?
anyanavicka [17]

Answer:

-<u>One Equation</u>: is set equal to a variable

Example:

y = 2x + 1

x + 3y = -12

You already have y, plug it back into x + 3y = -12

x + 3(2x + 1) = -12

x + 6x + 3 = -12

7x + 3 = -12

(Subtract 3 from each side)

7x = -15

(Divide by 7)

x = - 2.14

-<u>No Equation</u>: is set equal to a variable

Example:

2x + y = 10

4× + 2y = -3

Subtract 2x from each side of 2x + y = 10, you should get y= -2x + 10. Now that you have found y, substitute y into 4x+ 2y = -3.

4x + 2(-2x + 10) = -3

4x + -4x + 20 = -3

(Subtract 20 from each side)

4x + -4x = -23

(Add 4x and -4x)

0 = -23

No Solution

<u>-Both</u><u> </u><u>Equations</u>: are set equal to a variable

Example:

y = x + 5

y = -x + 3

(you already have y so plug it into the other equation to solve for x)

-x + 3 = x + 5

(Add -x on both sides)

3 = 2x + 5

(subtract 5 from both sides)

-2 = 2x

(Divide by 2 on each side)

x = -1

I hope this helped!

8 0
2 years ago
Evaluate the surface integral. s x ds, s is the part of the plane 18x + 9y + z = 18 that lies in the first octant.
IceJOKER [234]
In the first octant, the given plane forms a triangle with vertices corresponding to the plane's intercepts along each axis.

(x,0,0)\implies 18x+9\cdot0+0=18\implies x=1
(0,y,0)\implies 18\cdot0+9y+0=18\implies y=2
(0,0,z)\implies 18\cdot0+9\cdot0+z=18\implies z=18

Now that we know the vertices of the surface \mathcal S, we can parameterize it by

\mathbf s(u,v)=\langle(1-u)(1-v),2u(1-v),18v\rangle

where 0\le u\le1 and 0\le v\le1. The surface element is

\mathrm dS=\|\mathbf s_u\times\mathbf s_v\|\,\mathrm du\,\mathrm dv=2\sqrt{406}(1-v)\,\mathrm du\,\mathrm dv

With respect to our parameterization, we have x(u,v)=(1-u)(1-v), so the surface integral is

\displaystyle\iint_{\mathcal S}x\,\mathrm dS=2\sqrt{406}\int_{u=0}^{u=1}\int_{v=0}^{v=1}(1-u)(1-v)^2\,\mathrm dv\,\mathrm du=\frac{\sqrt{406}}3
5 0
3 years ago
A right rectangular prism has a volume of 144 cubic meters. The prism is 8 meters long and 3 meters high. What is the width of t
Cerrena [4.2K]

Answer:

The possible lengths and widths of the prism will be all those positive ordered pairs whose multiplication is equal to

Step-by-step explanation:

we know that

The volume of a rectangular prism is equal to

where

B is the area of the rectangular base

h is the height of the prism

In this problem we have

substitute and solve for B

-----> area of the rectangular base

therefore

The possible lengths and widths of the prism will be all those positive ordered pairs whose multiplication is equal to

Step-by-step explanation:

5 0
2 years ago
Read 2 more answers
What fraction accurately represents the decimal 2.3
timama [110]

Answer:

23/10. or 2  3/10

Step-by-step explanation:

6 0
3 years ago
Read 2 more answers
How many kilograms of coffee worth 40/kg must be mixed with coffee worth $11/kg to give 12kg of coffee worth $9.50/kg
Kazeer [188]

Answer:

0.62kg

Step-by-step explanation:

Let

x = 40/kg coffee

y = 11/kg coffee

two equations can be derived from the question

x + y = 12 equation 1

40x + 11y = 114 (9.5 x 12)  equation 2

multiply equation 1 by 11

11x + 11y = 132 equation 3

subtract eqn 3 from eqn 2

29x = 18

divide both sides of the equation by 29

x = 0.62kg

4 0
2 years ago
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