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Helga [31]
3 years ago
5

The average score of 100 students taking a statistics final was 70 with a standard deviation of 7. Assuming a normal distributio

n, what test score separates the top 25% of the students from the lower 75% of students?
Mathematics
1 answer:
san4es73 [151]3 years ago
8 0

Answer:

74.72

Step-by-step explanation:

Given

mean\left ( \mu \right )=70

Standard deviation \left ( \sigma \right )=7

For Top 25%

P\left ( Z

and Z value for 75 % is 0.6744

Thus score which separates the Top 25% of students is

=\mu +\sigma \cdot Z

=70+7\cdot 0.6744=74.7208

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Which other parts must be equal for triangle ABC= triangle MTR by
lesya692 [45]

Answer:

see below

Step-by-step explanation:

ASA stands for <u>Angle</u><u>-side-Angle</u>

thus, for ∆ABC\cong∆MTR

\displaystyle  \angle C  \cong  \angle R

SAS stands for <u>Side-angle-Side </u>

thus,for ∆ABC\cong∆MTR

\displaystyle \overline{  MR }\cong  \overline{MT}

likewise,

AAS stands for <u>Angle-Angle-Side</u>

thus,for ∆ABC\cong∆MTR

\displaystyle  \angle M \cong \angle T

7 0
2 years ago
The random variable X has the following probability mass function.X -1 0 2 6 7P(x) 0.3 0.1 0.3 0.2 0.1Answer the next 4 question
olga2289 [7]

Answer:

Step-by-step explanation:

Given that X has the following pdf.

x -1 0 2 6 7 Total

P(X) 0.3 0.1 0.3 0.2 0.1 1

xP(X) -0.3 0 0.6 1.2 0.7 2.2

x^2P(X) 0.3 0 1.2 7.2 4.9 13.6

     

Var(x) 13.6-2.2^2  8.76    

Std dev   2.959729717    

5) P( -1 < X ≤ 2) = P(0)+P(2)\\= 0.1+0.3=0.4

6. Find the cumulative distribution function F(x) and calculate F(3.2) =

x -1 0 2 6 7

P(X) 0.3 0.1 0.3 0.2 0.1

F(x) 0.3 0.4 0.7 0.9 1

F(3.2) = P(X<3.2) = ___F(X<6) = 0.7__________

7. E(X) = ______2.2_____

8. Var(X) = ____8.76______

3 0
3 years ago
a red ball and 4 white ball are in a box if two balls are drawn without replacement ,what is the probability of getting a red ba
BARSIC [14]

The probability is 1/5 to get a red ball in 1st draw and a white ball in 2nd draw.

<u>Step-by-step explanation:</u>

  • There are 1 red ball and 4 white balls in a box.
  • The total number of balls in the box = 1 red + 4 white = 5 balls.

The two balls are drawn without replacement.

<u>Drawing the first ball :</u>

The first draw should be a red ball.

The probability to get a red ball = No.of red balls / Total balls in the box.

We know that, No. of red balls is 1 and total balls in the box is 5.

P(red ball) = 1/5

<u>Drawing the second ball :</u>

The second draw should be a white ball.

The probability to get white ball = No.of white balls / Total balls in the box.

We know that,

No. of white balls is 4.

The total balls in the box after the first draw will be 4 balls.

P(white ball) = 4/4

The probability of getting a red ball on the first drawn and a white ball on the second​ draw = P(red ball) × P(white ball)

⇒ (1/5) × (4/4)

⇒ 4/20

⇒ 1/5

Therefore, the probability is 1/5 to get a red ball in 1st draw and a white ball in 2nd draw.

3 0
2 years ago
Help me out here pleaseeeeeee
Sveta_85 [38]

Answer:

(4, 80) Which is L

Step-by-step explanation:

First number should be on the X axis and the second on the Y axis.

6 0
3 years ago
A bird flies up and then down again, approximately following the
BaLLatris [955]

Answer:

  • 112.5 ft

Step-by-step explanation:

The maximum is achieved at vertex of parabola.

The x- coordinate of the vertex is determined by x = - b/(2a).

  • x = - 15/(-0.5*2) = 15

The maximum height is the corresponding y- coordinate

  • y = - 0.5(15²) + 15(15) = 112.5 ft
4 0
2 years ago
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