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2 years ago

A test had a mean of 72% and a standard deviation of 8 what is the z-score for a test score of 85?

Mathematics

1 answer:

PolarNik [594]2 years ago

3 0

Answer:

The answer to this question is within 2 stabdard deviations

Step-by-step explanation:

to get the score of 85 you got to add the deviation value to the mean whuch creates the deviation. do that multiple times and you get a multiple deviation

72+8=80+8 is 88

88 is greater than 85 so a test score of 85 is within 2 standard deviations of the mean

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Division was used in the first example.

VLD [36.1K]

Ok

Sulition because I said do

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2 years ago

What is the area of a triangle with vertices (3,0) (9,0) (7,6)

Nezavi [6.7K]

Answer:

The area of the triangle is of 21 units of area.

Step-by-step explanation:

The area of a triangle with three vertices $(x_1,y_1),(x_2,y_2),(x_3,y_3)$ is given by the determinant of the following matrix:

$A = \pm 0.5 \left|\begin{array}{ccc}x_1&y_1&1\\x_2&y_2&1\\1_3&y_3&1\end{array}\right|$

In this question:

Vertices (3,0) (9,0) (7,6). So

$A = \pm 0.5 \left|\begin{array}{ccc}3&0&1\\9&0&1\\7&7&1\end{array}\right|$

$A = \pm 0.5(3*0*1+0*1*7+1*9*7-0*7*1-0*9*1-3*1*7)$

$A = \pm 0.5*(63-21)$

$A = \pm 0.5*42 = 21$

The area of the triangle is of 21 units of area.

5 0

2 years ago

Find the area and perimeter.

lara [203]

Answer:

Step-by-step explanation:

Perimeter of triangle = 4x - 3 + x + 9 + 8

= 4x + x - 3 + 9 + 8

= 5x + 14

Area = $\frac{1}{2}*base *height$

$= \dfrac{1}{2}*8*3x\\\\= 4 * 3x\\\\= 12x$

8 0

2 years ago

PLEASE HURRY 9x^2 + 64 = 0 I NEED THE WORK SHOWN IN ORDER TO GET CREDIT

seropon [69]

Answer:

x = ± $\frac{8}{3}$ i

Step-by-step explanation:

subtract 64 from both sides

9x² = - 64 ( divide both sides by 9 )

x² = - $\frac{64}{9}$ ( take the square root of both sides )

x = ± $\sqrt{-64/9}$ = ± $\frac{8}{3}$ i

6 0

3 years ago

Read 2 more answers

Find the value of x at which the function has a possible relative maximum or minimum point. (Recall that e Superscript x is pos

shutvik [7]

Answer:

x= -11/4 is a maximum.

Step-by-step explanation:

Remember that a function has its critical points where the derivative equal zero. Therefore we need to compute the derivative of this function and find the points where the derivative is zero. Using the chain rule and the product rule we get that

$f'(x)= -e^{-4x}(11+4x)$

And then we get that if $11+4x = 0$ then $x = -11/4$ . So it has a critical point at $x = -11/4$ .

Now, if the second derivative evaluated at that point is less than 0 then the point is a maximum and if is greater than zero the point is a minimum.

Since

$f''(x) = 8e^{-4x} (5+2x)\\f''(-11/4) = -239496.56$

x= -11/4 is a maximum.

6 0

3 years ago