It is assumed that the test results for a class follow a normal distribution with a mean of 78 and a standard deviation of 36. If you know that a student's grade is greater than 72, what is the probability that it is greater than 84? What do I know? What do I want to find out? What do we expect the answer to be? How do I go from what I know to what I want to find? Does this answer seem reasonable?

Answers

Answer 1

Answer:

0.7143

- You know the minimum possible grade of the student

- You want to find out the probability that that grade which is greater than 72 is also greater than 84

- Expect the answer to be 0.7143

- The explanation/steps is given below

- The answer seems (and is) reasonable. You only created a new lower limit.

Step-by-step explanation:

Distribution Type: Normal

Mean: 78

Standard deviation: 36

Range of marks: [78 - 36], [78 + 36]  = [42 to 114]

If you know that a student's grade is greater than 72, what is the probability that it's greater than 84?

In this case, the full probability level is between 72 and the upper limit of 114 (instead of between 42 and 114). First, find the fraction of this probability.

[114 - 72] ÷ [114 - 42]  = 42/72  = 0.5833

So, the probability of a student's mark falling between 72 and 114 is 0.5833.

Now making this a whole interval, 114 - 72 = 42

What fraction of this interval of 42 will bear marks between 84 and 114?

[114 - 84]  = 30

30/42  = 0.7143

Because of the first part of the question "If you know (are sure) that a student's grade is greater than 72...", your answer stops at 0.7143, since 72 was used as the lower limit.


Related Questions

The problems in this lesson review basic arithmetic skills.

Answers

Answer:

false

Step-by-step explanation:

anyone know thisssss​

Answers

See the attachment.....

hellpppppp please I will give brainliest​

Answers

Answer:

I think the answer is y=2x-2

Hope it is correct! The x is positive because the angle is pointing to the right, and the -2 came from the position of the line.

Step-by-step explanation:

Answer:

D

Step-by-step explanation:

Write each set of numbers in set-builder and interval notation

X>50

Answers

Answer:

[tex]\{x\ E\ Z\ |\ x > 50\}[/tex] ---- Set Builder

(50, ∞)  ---- Interval Notation

Step-by-step explanation:

Given

x > 50

Required

Write as a

- Set builder

- Interval notation

As Set Builder:

x > 50 means that x is an integer and x is greater than 50.

In set builder notation, integers are represented with z.

So, the above can be represented as:

[tex]\{x\ E\ Z\ |\ x > 50\}[/tex]

This translates to:

x is a member of the set of integers such that x is greater than 50

As Interval Notation:

In interval notation, we make use of brackets to represent the intervals.

In this case > is represented by (a,b)

Where a and b are the intervals of the notation

Since x > 50, then a = 50 and b = ∞ because we only know the starting point and not the end point.

Hence: x > 50 in interval notation is (50, ∞)

(3x-15)(2x+7) what is x

Answers

Answer:

The chosen topic is not meant for use with this type of problem. Try the examples below.

2 = |3x|

−4/5x + 1/25 = 0

3x = 4 − x

Answer

Step-by-step explanation:

This has to be equal to something in order to solve it. I'm going to guess that it is equal to 0

(3x-15)(2x+7) = 0

That means that

3x - 15 = 0

3x = 15

x = 15/3

x = 5

or

2x + 7 = 0

2x = - 7

x = -7/2

x = - 3.5

The only other thing I can think of that this could equal is multiplying the two binomials together.

3x * 2x = 6x^2

3x*7 = 21x

-15*2x = - 30x

-15 * 7 = - 105

6x^2 - 7x - 105

But that does not solve for x.

please some help me with this.​

Answers

X=14

every triangle equals 180 when adding all the angles together 72+36 = 108 So 180-108 = 72 (also note this is an isosceles triangle)

Now 72-16 = 56
56÷4 = 14

can someone teach me how to isolate variables in algebra

Answers

Here are the steps to isolate variables in algebra

please help me ig :/

Answers

Answer:

either A&C of B&C

Step-by-step explanation:

why i think that is because perpendicular lines are defined as two lines that meet or intersect each other at right angles (90°). and both A&C of B&C are (90°).

Assume that SAT scores are normally distributed with mean 1518 and standard deviation 325. Round your answers to 4 decimal placesa. If 100 SAT scores are randomly selected, find the probability that they have a mean less than 1500.b. If 64 SAT scores are randomly selected, find the probability that they have a mean greater than 1600c. If 25 SAT scores are randomly selected, find the probability that they have a mean between 1550 and 1575d. If 16 SAT scores are randomly selected, find the probability that they have a mean between 1440 and 1480.e. In part c and part d, why can the central limit theorem be used even though the sample size does not exceed 30?

Answers

Answer:

a. 0.2898

b. 0.0218

c. 0.1210

d. 0.1515

e. This is because the population is normally distributed.

Step-by-step explanation:

Assume that SAT scores are normally distributed with mean 1518 and standard deviation 325. Round your answers to 4 decimal places

We are using the z score formula when random samples

This is given as:

z = (x-μ)/σ/√n

where x is the raw score

μ is the population mean

σ is the population standard deviation.

n is the random number of samples

a.If 100 SAT scores are randomly selected, find the probability that they have a mean less than 1500.

For x = 1500, n = 100

z = 1500 - 1518/325/√100

z = -18/325/10

z = -18/32.5

z = -0.55385

Probability value from Z-Table:

P(x<1500) = 0.28984

Approximately = 0.2898

b. If 64 SAT scores are randomly selected, find the probability that they have a mean greater than 1600

For x = 1600, n = 64

= z = 1600 - 1518/325/√64.

z= 1600 - 1518 /325/8

z = 2.01846

Probability value from Z-Table:

P(x<1600) = 0.97823

P(x>1600) = 1 - P(x<1600) = 0.021772

Approximately = 0.0218

c. If 25 SAT scores are randomly selected, find the probability that they have a mean between 1550 and 1575

For x = 1550, n = 25

z = 1550 - 1518/325/√25

z = 1550 - 1518/325/5

z = 1550 - 1518/65

= 0.49231

Probability value from Z-Table:

P(x = 1550) = 0.68875

For x = 1575 , n = 25

z = 1575 - 1518/325/√25

z = 1575 - 1518/325/5

z = 1575 - 1518/65

z = 0.87692

Probability value from Z-Table:

P(x=1575) = 0.80974

The probability that they have a mean between 1550 and 1575

P(x = 1575) - P(x = 1550)

= 0.80974 - 0.68875

= 0.12099

Approximately = 0.1210

d. If 16 SAT scores are randomly selected, find the probability that they have a mean between 1440 and 1480

For x = 1440, n = 16

z = 1440 - 1518/325/√16

= -0.96

Probability value from Z-Table:

P(x = 1440) = 0.16853

For x = 1480, n = 16

z = 1480 - 1518/325/√16

=-0.46769

Probability value from Z-Table:

P(x = 1480) = 0.32

The probability that they have a mean between 1440 and 1480

P(x = 1480) - P(x = 1440)

= 0.32 - 0.16853

= 0.15147

Approximately = 0.1515

e. In part c and part d, why can the central limit theorem be used even though the sample size does not exceed 30?

The central theorem can be used even though the sample size does not exceed 30 because the population is normally distributed.

Find the slope of the line graphed below.

Answers

Answer:

(rise/run) 5/4

decimal ver: 1.25

Answer:

[tex]\frac{5}{4}[/tex]

Step-by-step explanation:

The line passes trough the points (2, 2) and (-2, -3).

[tex]m=\frac{rise}{run}=\frac{-3-2}{-2-2}=\frac{-5}{-4} =\boxed{\frac{5}{4}}[/tex]

Hope this helps.

simplify the like terms

-2x\:+\:3y\:-\:3xy\:+2yz\:-\:3x^2y\:+5x\:-\:4y+3xy

Answers

Answer:

[tex]-2x+3y-3xy+2yz-3x^2y+5x-4y+3xy = 3x-y+2yz-3x^2y[/tex]

Step-by-step explanation:

Given

[tex]-2x+3y-3xy+2yz-3x^2y+5x-4y+3xy[/tex]

Required

Simplify

[tex]-2x+3y-3xy+2yz-3x^2y+5x-4y+3xy[/tex]

We start by collecting like terms

[tex]-2x+5x-4y+3y+3xy-3xy+2yz-3x^2y[/tex]

Then simplify like terms:

[tex]3x-y+0+2yz-3x^2y[/tex]

[tex]3x-y+2yz-3x^2y[/tex]

Conclusively, when [tex]-2x+3y-3xy+2yz-3x^2y+5x-4y+3xy[/tex] is simplified, the result is [tex]3x-y+2yz-3x^2y[/tex]

Hence:

[tex]-2x+3y-3xy+2yz-3x^2y+5x-4y+3xy = 3x-y+2yz-3x^2y[/tex]

A nursery owner buys 9 panes of glass to fix some damage to her greenhouse. The 9 panes cost
$25.65. Unfortunately, she breaks 2 more panes while repairing the damage. What is the cost of
another 2 panes of glass?
Another 2 panes of glass cost $____

Answers

Step-by-step explanation:

so first you would ave to find the  unit rate,so 25.65/9=$2.85 then you would multiply 2.85*2 for the other 2 that she broke. You would get $5.70 add that to the 25.65 you  would get $31.35. the two panes of glass=$5.70 and altoger with the two pans of glass you would get $31.35

a snail crawls 3/4 inches in 1/5 of a minute how long will it take the snail to crawl 1/2 in?

Answers

Answer:

15/4

Step-by-step explanation:

Whenever you are working with a question of rate where two different quantities are being compared, the required units will indicate which quantity is to be divided by which.

3/4 divided by 1/5

3/4 times 5/1 (multiply reciprocal)

=15/4

I havent done this in a while so im not entirely sure.

Question 1
2 (4x - 1) + 6
Equivalent to what

Answers

Answer:

2 (4x - 1) + 6 = 8x + 4 = 4(2x+1)

Step-by-step explanation:

2 (4x - 1) + 6

= (2*4x + 2*-1) + 6

= 8x - 2 + 6

= 8x + 4

= 4/(2x+1)

Answer:

4(2x+1)

Step-by-step explanation:

First, factor it out:

2(4x-1+3)

Then calculate:

2(4x+2)

Factor out 2:

2 • 2(2x+1)

Then finally multiply:

4(2x+1)

Consider the function shown on the graph. Complete the statements to make them true

Answers

Answer:

Domain: x ≥ -5

Range: y ≥ -2

Step-by-step explanation:

The domain are the set of x-values of the function that are plotted on the x-axis. The domain of the graph given are x-values that are equal to or greater than -5.

Therefore:

✅Domain: x ≥ -5

The range from the graph given the y-values plotted on the y-axis against their corresponding x-values that are equal to or greater than -2.

Therefore:

✅Range: y ≥ -2

Find the least common multiple of 7,9 and 21

Answers

Free LCM Calculator determines the least common multiple (LCM) between 9 and 21 the smallest integer that is 63 that is divisible by both numbers. Least Common Multiple (LCM) of 9 and 21 is 63.
...
Prime Factorization of 21.
3 21
7 7
1

A tailor charge $560 for a suit of clothes and gives a discount of 12% for cash. Calculate the discounted price for a suit of clothes.​

Answers

answer is 67.2!!!!!!!

Answer:

$492.80

Step-by-step explanation:

The discount= 12%*$560/100%

= $67.20

The discounted= Selling price- discount

= $560 - $67.20

= $492.80

we cannot survive without water give reason why​

Answers

Answer:

Because we don't have life without water it is precious

A store pays $49.14 for an easel. The Store markes up the price by %50. What is the amount the make-up

Answers

Answer:

$56.51

Step-by-step explanation:

Given parameters:

Cost price by the store = $49.14

Amount of mark up = 50%

Unknown:

Make- up price  = ?

Solution:

Since the price was increased by 50% more, to find the mark up price, we can find 50% of the cost price and add the value to the cost price.

Also;

 Make-up price  =( 1 + [tex]\frac{50}{100}[/tex] ) x $49.14

                           = 1.15 x $49.14

                            = $56.51

Factor the algebraic expression 18a + 14 18a + 14 = (Factor completely.)

Answers

Answer:

You cannot factor that any more.

Step-by-step explanation:

The equation is as simple as it can be.

What are the different ways to write multiplication?

Answers

Answer:

Distribution, equal groups, skip counting, repeated addition, and array.

Step-by-step explanation:

• x it help leave my first like :)

Please help me thanks.

Answers

y=(-2x)+5

Step-by-step explanation:

what is the decimal multiplier to decrease by 8.4

Answers

Answer:0.916

The decimal multiplier to decrease by 8.4% is 0.916.

Step-by-step explanation:

There are 40 students in a class.
Each student walks to school or cycles to school or gets the bus to school
There are 22 girls in the class.
9 of the girls walk to school.
7 of the boys cycle to school.
6 of the 10 students who get the bus to school are boys.
Find the number of these students who walk to school.

Answers

Step-by-step explanation:

Total no. of students = 40

Total no. of girls = 22

Total no. of boys = 40 - 22 = 18

No. of girls walking to school = 9

No. of girls who cycle to school = 22 - 9

No. of boys who cycle to school = 7

No. of students who take the bus = 10

(6 boys and 4 girls)

No. of boys who walk to school = 18 - (7 + 6) = 5

Total no. of students who walk to school = 9 + 5 = 14

The number of students who walked to school was 14 students

What is an Equation?

Equations are mathematical statements with two algebraic expressions flanking the equals (=) sign on either side.

It demonstrates the equality of the relationship between the expressions printed on the left and right sides.

Coefficients, variables, operators, constants, terms, expressions, and the equal to sign are some of the components of an equation. The "=" sign and terms on both sides must always be present when writing an equation.

Given data ,

The equations will be ,

Let the total number of students in the class be A = 40 students

The number of girls in the class = 22 students

The number of boys in class = total number of students - number of girls

                                                = 40 - 22

                                                = 18 students

Now ,

The number of girls who walked to school = 9 students

The number of boys who cycled to school = 7

So , remaining boys = 18 - 7

                                 = 11 students

The number of boys who take bus to school = 6 students

So , remaining boys = 11 - 6

                                 = 5 students

Therefore , the remaining boys in the class walks to school = 5 students

So , the equation will be

And , the total number of students who walked to school =
number of boys in the class that walks to school + number of girls who walked to school

Total number of students who walked to school = 9 + 5

                                                                                = 14 students

Hence , The number of students who walked to school was 14 students

To learn more about equations click :

https://brainly.com/question/10413253

#SPJ2

Which step is the most efficient way to find the solution of p + 5 > -13

Answers

Answer:

subtracting 5 from both sides

Step-by-step explanation:

please mark brainliest lol :)

Answer:

p>-18

Step-by-step explanation:

The most efficient way to find the solution of p+5>-13 is to subtract 5 from both sides, getting p>-18

help me please I don't understand ​

Answers

Step-by-step explanation:

Option 3 must be correct.

URGENT WILL GIVE BRAINLIEST——-Which of the following functions is quadratic?

Answers

Answer:

D

Step-by-step explanation:

A school eams S70 from selling 50 tickets for the school play. Each ticket costs the same amount
How much does the school eam for 1 ticket?
Enter your answer in the box below.

Answers

Answer:

$1.40

Step-by-step explanation:

I used a unit rate to understand it.

$70/50

70÷ 50= 1.4

50÷50=1

1.4/1 = 1.4 OR $1.40, adding a zero doesn't change it amount, it just places a filler, so the final answer is, one dollar and forty cents.

50pesos de 100 cuánto es el porciento​

Answers

It is 50% because it is half of the total

Answer:

50%

Step-by-step explanation:

El 100% es 100  

Y X es 50  

Entonces si 50 es la mitad de 100

Seria 50%

The first term of a sequence is 9 and the common difference is 5. Which of the following is the fifth term of the sequence?

Answers

Answer:

29

Step-by-step explanation:

9+5=14+5=19+5=24+5=29

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