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3 years ago

Suppose that a normal distribution has a mean of 20 and a standard deviation of 4. What is the z-score of 13?

Mathematics

1 answer:

Papessa [141]3 years ago

5 0

Answer:

-1.75.

Step-by-step explanation:

The z-score = (n - m) / d where n is the value (13) m = mean and d = standard deviation.

= (13 - 20) / 4

= -1.75 (answer)

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Paul spelled 6 out of 16 words correctly on his spelling test. What fraction of the words did he misspell?

olya-2409 [2.1K]

Answer:

5/8 are spelled incorrectly

Step-by-step explanation:

There are 16 words

He spelled 6 correctly

That means he spelled 16-6 = 10 incorrectly

The fraction spelled incorrectly is wrong/total

10/16

Simplify by dividing the top and bottom by 2

5/8

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4 years ago

Read 2 more answers

Vertex form of <br> y=x^2-4x-9

Scrat [10]

Complete the square
first isolate x terms
y=(x^2-4x)-9
complete square inside (take 1/2 of square of b )
-4/2=-2, (-2)^2=4
add 4-4 inside
y=(x^2-4x+4-4)-9
complete the square
y=((x-2)^2-4)-9
y=(x-2)^2-4-9
y=(x-2)^2-13

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4 years ago

9. Combine the radical expression, if possible.

Anastaziya [24]

Answer:

we conclude that:

$3\sqrt{125}+4\sqrt{20}=23\sqrt{5}$

Hence, the last option i.e. $23\sqrt{5}$ is correct.

Step-by-step explanation:

Given the expression

$3\sqrt{125}+4\sqrt{20}$

Combining the radical expressions

$3\sqrt{125}+4\sqrt{20}$

let us first solve

$3\sqrt{125}$

$=3\sqrt{5^3}$

$=3\sqrt{5^2\cdot \:5}$

Apply radical rule: $\sqrt{ab}=\sqrt{a}\sqrt{b},\:\quad \:a\ge 0,\:b\ge 0$

$=3\sqrt{5^2}\sqrt{5}$

Apply radical rule: $\sqrt{a^2}=a,\:\quad \:a\ge 0$

$=3\cdot \:5\sqrt{5}$

$=15\sqrt{5}$

Thus,

$3\sqrt{125}=15\sqrt{5}$

similarly solving

$4\sqrt{20}$

$=4\sqrt{2^2\cdot \:5}$

Apply radical rule: $\sqrt{ab}=\sqrt{a}\sqrt{b},\:\quad \:a\ge 0,\:b\ge 0$

$=4\sqrt{2^2}\sqrt{5}$

Apply radical rule: $\sqrt{a^2}=a,\:\quad \:a\ge 0$

$=4\cdot \:2\sqrt{5}$

$=8\sqrt{5}$

Thus,

$4\sqrt{20}=8\sqrt{5}$

so we get

$3\sqrt{125}=15\sqrt{5}$

$4\sqrt{20}=8\sqrt{5}$

so the expression becomes

$3\sqrt{125}+4\sqrt{20}=15\sqrt{5}+8\sqrt{5}$ ∵ $3\sqrt{125}=15\sqrt{5}$ , $4\sqrt{20}=8\sqrt{5}$

$=23\sqrt{5}$ ∵ $15\sqrt{5}+8\sqrt{5}=23\sqrt{5}$

Therefore, we conclude that:

$3\sqrt{125}+4\sqrt{20}=23\sqrt{5}$

Hence, the last option i.e. $23\sqrt{5}$ is correct.

7 0

3 years ago

How do you do this problem

Fudgin [204]

A triangle is 180°; therefore:
x = 180-52-43
x = 85
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3 years ago

Which of the followings are the amplitude and the equation of the midline of the curve

Juli2301 [7.4K]

Answer:

15 or -4

Step-by-step explanation:

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3 years ago