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
Arada [10]
3 years ago
6

In an Algebra II class with 135 students, the final exam scores have a mean of 72.3 and standard deviation 6.5. The exams on the

exams are whole numbers, and the grade pattern follows a normal curve.
a. Find the number of students who receive grades from two to three standard deviations above the mean? Explain how you got your answer!

b. Find the number of students who scored between 65.8 and 72.3. Explain how you found your answer!
Mathematics
1 answer:
gregori [183]3 years ago
4 0
Population = 135 students
Mean score = 72.3
Standard deviation of the scores = 6.5

Part (a): Students from 2SD and 3SD above the mean
2SD below and above the mean includes 95% of the population while 3SD includes 99.7% of the population.
95% of population = 0.95*135 ≈ 129 students
99.7% of population = 0.997*135 ≈ 135 students

Therefore, number of students from 2SD to 3SD above and below the bean = 135 - 129 = 6 students.
In this regard, Students between 2SD and 3SD above the mean = 6/2 = 3 students

Part (b): Students who scored between 65.8 and 72.3
The first step is to calculate Z values
That is,
Z = (mean-X)/SD
Z at 65.8 = (72.3-65.8)/6.5 = 1
Z at 72.3 = (72.3-72.3)/6.5 = 0
Second step is to find the percentages at the Z values from Z table.
That is,
Percentage of population at Z(65.8) = 0.8413 = 84.13%
Percentage of population at (Z(72.3) = 0.5 = 50%
Third step is to calculate number of students at each percentage.
That is,
At 84.13%, number of students = 0.8413*135 ≈ 114
At 50%, number of students = 0.5*135 ≈ 68

Therefore, students who scored between 65.8 and 72.3 = 114-68 = 46 students
You might be interested in
9 hundreds =equals <br><br> tens
Lelechka [254]
90 tens hopefully this helped
3 0
3 years ago
Read 2 more answers
4×0.23 what is it i don't no
kramer
4*0.23
0.92 
the answer is 0.92 

8 0
3 years ago
Read 2 more answers
Algebra 1 question 4.
Brrunno [24]

Greetings!

To start this problem, let's first assign a variable for the missing, consecutive odd numbers. Since they are consecutive and odd, we add two.

<u>Proof:</u> <em>3-1=2, 5-3=2</em>

The first, consecutive, odd number: x

The second, consecutive, odd number: x+2

The third, consecutive, odd number: x+4

The fourth, consecutive, odd number: x+6

The sum of the values are equal to 3 times the sum of the first two numbers, of which this is equal to 35 less than the fourth number. Let's create an equation to simplify this:

3((x)+(x+2))=(x+6)-35

Complete the operations inside the parenthesis:

3(2x+2)=(x+6)-35

Distribute the parenthesis (utilizing the distributive property)

(((2x)(3))+((2)(3)))=(x+6)-35

(6x+6)=(x+6)-35

Simplify both sides:

6x+6=x-29

Add -6 and -x to both sides of the equation:

(6x+6)+(-6)+(-x)=(x-29)+(-6)+(-x)

5x=-35

Divide both sides of the equation by 5:

\frac{5x}{5}=\frac{-35}{5}

x=-7

If x is equal to -7:

x+2=-5

x+4=-3

x+6=-1

The four numbers are:

\boxed{-7,-5,-3,-1}

I hope this helps!

-Benjamin

4 0
3 years ago
Read 2 more answers
A store sells pool floats.
Andrei [34K]

Step-by-step explanation:

the original retail price was 120% of the manufacturer price (100% manufacturer price + 20% markup).

now, the whole retail price is reduced by 12%.

that means we have to subtract 12% from the 120%.

but careful, we cannot just do 120-12=108.

that is simply because these 120% are now for this calculation the new basic amount and therefore 100%.

we actually need to calculate and subtract 12% of 120 to get the new percentage over the manufacturer price.

we do this by multiplying 120 by (100-12)/100 = 88/100 = 0.88 :

120 × 0.88 = 105.6%

so, the new retail price is now only 5.6% over the manufacturer price.

6 0
2 years ago
Solve for x 2 + x = - 5
Scrat [10]
X= -7

2+x=-5 if you move the constant to the right side it would be x=-5-2 which equals -7
6 0
3 years ago
Read 2 more answers
Other questions:
  • Simplify the fraction 8/36
    12·1 answer
  • How many miles does he drive in six hours?
    15·1 answer
  • Which monomial is a perfect cube?<br><br> 16x6<br> 27x8<br> 32x12<br> 64x6
    15·2 answers
  • For which values of P and Q does the following equation have infinitely many solutions ?
    6·1 answer
  • Which mixed number is equivalent to the improper fraction?<br> 14/9
    13·1 answer
  • Two sides of a triangle measures 20 cm in 30 cm. Which of the following is a measure of
    10·1 answer
  • Jake found a turtle at Collins Hill Park. He has an aquarium in the shape of a right rectangular prism is 10.5 inches long, 5 in
    11·2 answers
  • The diameter of the figure to the left is 9 cm.
    14·1 answer
  • Please Help!! I will give brainliest<br><br> The question is attached below
    7·1 answer
  • Which is the graph of a quadratic equation that has a positive discriminant?
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!