1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
oksano4ka [1.4K]
3 years ago
11

A set of test scores is normally distributed with a mean of 130 and a standard deviation of 30 What score is necessary to reach

the 75th percentile? Select the closest answer
Mathematics
1 answer:
nlexa [21]3 years ago
7 0

Answer:

A score of 150.25 is necessary to reach the 75th percentile.

Step-by-step explanation:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

A set of test scores is normally distributed with a mean of 130 and a standard deviation of 30.

This means that \mu = 130, \sigma = 30

What score is necessary to reach the 75th percentile?

This is X when Z has a pvalue of 0.75, so X when Z = 0.675.

Z = \frac{X - \mu}{\sigma}

0.675 = \frac{X - 130}{30}

X - 130 = 0.675*30

X = 150.25

A score of 150.25 is necessary to reach the 75th percentile.

You might be interested in
Explain why parallelograms are always
Mars2501 [29]

Answer: Parallelogram is a kind of quadrilateral where as there are some quadrilaterals (like trapezoid , kite, .. ) that do not satisfy the properties of parallelograms.

Step-by-step explanation:

A quadrilateral is a closed polygon having fours sides.

A parallelogram is a kind of quadrilateral having following properties:

Its opposite sides and opposite angles are equal.

The sum of adjacent angles is 180°.

The diagonal of parallelogram bisect each other.

A Trapezoid is also a quadrilateral . It has only one pair of parallel sides. (The other one are not parallel).

So , all quadrilaterals not parallelograms.

Therefore, parallelograms are always quadrilaterals but quadrilaterals are sometimes parallelograms because parallelogram is a kind of quadrilateral where as there are some quadrilaterals (trapezoid , kite, .. ) ) that do not satisfy  the properties of parallelograms.

plz mark me as brainliest :)

6 0
2 years ago
F(x)=-3/5x+k and if f(30)=-11 what is the value of k
Kruka [31]

Answer:

k=20.

Explanation: First we find where f(x) has its local extrema: f'(x)=3x2−10x+3. The critical points are roots of the equation: 3x2−10x+3=0.

6 0
2 years ago
1.A cube has side lengths of 15 inches, what is the surface area and volume of the cube? 2. A cube has side lengths of 8 inches,
omeli [17]

Answer:

Cube 1: 3375 cubed inches, 1350 inches squared.

Cube 2: 512 cubed inches, 384 inches squared.

Step-by-step explanation:

Formula for Volume of a Cube:  V=s^3\\ (s - side length)

Formula for Surface Area of a Cube: SA=6s^2 (s- side length)

<h3>For Cube 1:</h3>

The side length's 15 inches.

Find the volume:

V=15^3\\\rightarrow 15*15*15=3375\\\boxed {V=3375}

The volume of cube one is 3375in³.

Find the surface area:

SA=6(15)^2\\\rightarrow 15^2 = 225\\SA = 6 * 225\\\boxed {SA=1350}

The surface area of cube 1 is 1350in².

<h3>For Cube 2:</h3>

The side length's 8 inches.

Find the volume:

V=8^3\\\rightarrow 8*8*8= 512\\\boxed {V=512}

The volume of cube two is 512in³.

Find the surface area:

SA=6(8)^2\\\rightarrow 8^2=64\\SA=6*64\\\boxed {SA=384}

The surface area of cube 2 is 384in².

<em>Brainilest Appreciated. </em>

3 0
3 years ago
Matt and Brian were solving a system of equations. They both noticed that the two lines had the same slope. Brian said that beca
mixas84 [53]

Answer:

it's answer is B.

Step-by-step explanation:

you're welcome:)

8 0
3 years ago
What is the slope of the line? (Enter the number only.)<br> Slope=
BigorU [14]
I think it’s 25 and two half’s
8 0
3 years ago
Read 2 more answers
Other questions:
  • Quickly solve (x+7)2=121, for x. Graph the solution on a number line.
    14·1 answer
  • The price of a jet ski was marked up 15% over the previous year's model. if the previous year's model sold for $500, what is the
    7·1 answer
  • Select all number that have an absolute value of 0.6​
    9·1 answer
  • If a system of linear equations has no solution, what do you know about the slopes and y-intercepts of the graphs of the equatio
    15·1 answer
  • Identify the expression as a numerical expression or a variable expression. For a variable expression, name the variable. 1 × 12
    12·2 answers
  • Please help me with this! Very much appreciate
    5·1 answer
  • Nina plots the locations of 4 places on a coordinate grid as given below (It is recommended that you work this out on graph pape
    8·1 answer
  • Jimmy wants to buy socks that cost $20 how much change does he receive if he gives the cashier $100?
    6·1 answer
  • Find the value of y ​
    15·1 answer
  • What is 75.6 divided by 4
    12·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!