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sergey [27]
1 year ago
12

Stats To quality for a police academy, applicants are given a lest of physical Itness. Ihe scores are normallyDistributed with a

mean of 64 and a standard deviation of 9. If only the top 20% of the applicants are selected,Find the cutoff score.
Mathematics
1 answer:
omeli [17]1 year ago
6 0

Since we want just the top 20% applicants and the data is normally distributed, we can use a z-score table to check the z-score that gives this percentage.

The z-score table usually shows the percentage for the values below a certain z-score, but since the whole distribution accounts to 100%, we can do the following.

We want a z* such that:

P(z>z^*)=0.20

But, to use a value that is in a z-score table, we do the following:

\begin{gathered} P(zz^*)=1 \\ P(zz^*)=1-0.20=0.80 \end{gathered}

So, we want a z-score that give a percentage of 80% for the value below it.

Using the z-score table or a z-score calculator, we can see that:

\begin{gathered} P(zNow that we have the z-score cutoff, we can convert it to the score cutoff by using:[tex]z=\frac{x-\mu}{\sigma}\Longrightarrow x=z\sigma+\mu

Where z is the z-score we have, μ is the mean and σ is the standard deviation, so:

\begin{gathered} x=0.8416\cdot9+64 \\ x=7.5744.64 \\ x=71.5744\cong72 \end{gathered}

so, the cutoff score is approximately 72.

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Your going to have to draw it out,but just look for the number on your number line and put a point above the number.
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3 years ago
PLSSS HELP IF YOU TURLY KNOW THISS
Andrej [43]

Answer:

<u><em>B</em></u>

Step-by-step explanation:

  • <em>4/1 * 1/3</em>
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4 0
2 years ago
Read 2 more answers
State how many imaginary and real zeros the function has.
myrzilka [38]
Hello,
Degre 5==> even number of imaginary roots and odd number of reals.

Real roots must be a divisor of 7.
Using Excel, we find


<span> <span><span> x  P(x) 
 </span><span>-7 0 </span>
<span> -6 1369
</span> <span> -5 1352
</span> <span> -4 867
</span> <span> -3 400
</span> <span> -2 125
</span> <span> -1 24
 </span><span>0 7
 </span><span>1 32
 </span><span>2 225
 </span><span>3 1000
 </span><span>4 3179
 </span><span>5 8112
 </span><span>6 17797
 </span><span>7 35000

So: one real root: 7 and 4 imaginary roots.

Answer B
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7 0
3 years ago
Quadratic equations and complex numbers PLEASE HELPPPP ASAP
kondor19780726 [428]

we are given

27x^3-1=0

we can also write it as

(3x)^3-(1)^3=0

now, we can use factor formula

a^3-b^3=(a-b)(a^2+ab+b^2)

we can use above formula

we get  

(3x)^3-(1)^3=(3x-1)((3x)^2+3x\times 1+(1)^2)

now, we can simplify it

27x^3-1=(3x-1)(9x^2+3x+1)

now, we can set it to 0

27x^3-1=(3x-1)(9x^2+3x+1)=0

and then we can solve for x

(3x-1)(9x^2+3x+1)=0

3x-1=0

x=\frac{1}{3}

9x^2+3x+1=0

now, we can use quadratic formula

x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}

now, we can plug values

and we get

x=\frac{-3\pm \sqrt{3^2-4\cdot \:9\cdot \:1}}{2\cdot \:9}

x=-\frac{1}{6}+i\frac{\sqrt{3}}{6},\:x=-\frac{1}{6}-i\frac{\sqrt{3}}{6}

So, we will get solution as

x=\frac{1}{3},\:x=-\frac{1}{6}+i\frac{\sqrt{3}}{6},\:x=-\frac{1}{6}-i\frac{\sqrt{3}}{6}...............Answer

5 0
3 years ago
Which statement correctly describes the location of the incenter of a triangle?
NemiM [27]

9514 1404 393

Answer:

  B)  The incenter is equidistant from all three sides of the triangle.

Step-by-step explanation:

The incenter is the center of the inscribed circle, which is tangent to all three sides. Hence, the distance from the incenter to each side is the radius of the circle. The incenter is equidistant from the sides of the triangle.

4 0
3 years ago
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