The mean examination mark of a random sample of 1390 students is 67% with a standard deviation of 8.1%.
How many students scored above 80%? (Round to the nearest student)

Answers

Answer 1

Answer:

76 students scored above 80%.

Step-by-step explanation:

Normal Probability Distribution

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

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

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 p-value, we get the probability that the value of the measure is greater than X.

The mean examination mark of a random sample of 1390 students is 67% with a standard deviation of 8.1%.

This means that [tex]\mu = 67, \sigma = 8.1[/tex]

Proportion above 80:

1 subtracted by the p-value of Z when X = 80, so:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{80 - 67}{8.1}[/tex]

[tex]Z = 1.6[/tex]

[tex]Z = 1.6[/tex] has a p-value of 0.9452.

1 - 0.9452 = 0.0548.

Out of 1390 students:

0.0548*1390 =  76

76 students scored above 80%.


Related Questions

What is the slope-intercept equation of the line below?

Answers

Answer:

y=-5/4x+3

Step-by-step explanation:

y=mx+c

m = (y1-y2)/(x1-x2) =(-2-3)/(4-0) =-5/4

sub the values y=3, x=0 to find c,

3 =-5/4(0) + c

c = 3

Find the length of the segment indicated. circles 4

Answers

I need more information, comment on my "answer".


In the equation 11 - 4(x +4) = 6x, the first step is to simplify 11 - 4.
True
False

Answers

Answer:

False

Step-by-step explanation:

You first need to distribute the -4 to (x+4).

please help with this on the picture

Answers

Answer:

There is not enough information to solve this problem :(

Find mPMA + mCMT. Please help..

Answers

PMA = 37

CMT =  101 - 54 =47

Total = 37 + 47 = 84

Answer: A. 84

Someone help me please

Answers

Answer:

y=4

Step-by-step explanation:

The triangle on the right is a 30-60-90 triangle

The ratio of sides in a 30-60-90 triangle is 1:√3:2

y:x:8

SO y will be 4 because 8/y=2/1

Do the two trapezoids in the figure appear to be similar? Why or why not?
options:

A)

They're not similar because only one pair of corresponding angles in the two trapezoids is congruent.

B)

They're similar because two pairs of corresponding angles in the two trapezoids are congruent.

C)

They're similar because one pair of corresponding angles in the two trapezoids is congruent.

D)

They're not similar because two pairs of corresponding angles in the two trapezoids are congruent.

Answers

Answer:

Option B,

They're similar because two pairs of corresponding angles in the two trapezoids are congruent

Answer:

They're not similar because only one pair of corresponding angles in the two trapezoids is congruent.

Step-by-step explanation:

HELP ME PLSSS SUMMER SCHOOL A HARD

Answers

Answer:

y=2x+8

Step-by-step explanation:

Hope this helps

Can you help with this

Answers

9514 1404 393

Answer:

  D, C

Step-by-step explanation:

The only two rational expressions that have appropriate denominators are ...

  1/(x² +6x) . . . contributes a factor of x to the denominator

  (x+2)/(x² -36) . . . contributes a factor of (x -6) to the denominator

The proper order in the expression is ...

  [tex]\displaystyle\dfrac{x+2}{x^2-36}-\dfrac{1}{x^2+6x}=\dfrac{x^2+x+6}{x(x-6)(x+6)}[/tex]

Answer:

(x+2/x^2-36) - (1/x^2+6x) = (x^2+x+6/x(x-6)(x+6))

Step-by-step explanation:

I hope that helps

What is the greatest common factor of 10 and 13?
ANSWER IN LESS THEN 3 MINS AND I'LL GIVE BRAINLIEST

Answers

Answer:

the answer for this would be 1

A health club sold ten memberships in one week for total of $3000. If male memberships cost $300 and female memberships cost $300, then how many male memberships and how female memberships were sold?

Answers

Answer:

Step-by-step explanation:

The reason you haven't gotten an answer to this is because in its current formatting, there is no answer. Here's what I mean:

The first equation is going to be concerning the NUMBER of memberships sold, where m is male and f is female. The total number of memberships was 10:

m + f = 10

Now for the money equation. The total amount of money made from that number of memberships was 3000, where male memberships cost $300 and so do the female memberships, giving us an equation of

300m + 300f = 3000

Go back to the first equation and solve for either m or f. I solved for m in terms of f:

m = 10 - f and sub that into the second equation for m to get:

300(10 - f) + 300f = 3000 and

3000 - 300f + 300f = 3000. Here is where you find the problem. The -300f and the 300f cancel each other out, leaving you with the fact that

3000 = 3000 which it does, but it doesn't give us any viable answer.

I would have to say that since we can't do math on this, that the most credible answer you'll find is that the same number of male and female memberships were sold because 5 male memberships cost $1500 (5 memberships at $300 a piece is $1500) and 5 female memberships also cost $1500.

1500 + 1500 = 3000

. Two mutually exclusive projects have projected cash flows as follows:
YEAR PROJECT A PROJECT B
0 Ksh. -2m Ksh. -2m
1 1m 0
2 1m 0
3 1m 0
4 1m 6m





Required:
a) Determine the internal rate of return for each project. [2 Marks]

b) Determine the net present value for each project at discount rates of 0, 5,10,20,30, and 35 percent. [2 Marks]

c) Plot a graph of the net present value of each project at the different discount rates. [2 Marks]

d) Which project would you choose? Why? [ 2 Marks]

e) What is each project’s MIRR if the cost of capital is 12 percent?

Answers

Answer:

yes

Step-by-step explanation:

 In one of the examples he is working on, he knows that the two coordinates (0,6) and
(8, 10) are on the function that he is deriving. Using the information from these two
coordinates, determine the slope and y-intercept of the function Mike is looking for, and
then write out the correct function.

Answers

9514 1404 393

Answer:

  y = 1/2x + 6

Step-by-step explanation:

The slope m is given by the formula ...

  m = (y2 -y1)/(x2 -x1)

  m = (10 -6)/(8 -0) = 4/8 = 1/2

The y-intercept is given by the formula ...

  b = y -mx

  b = 6 -(1/2)(0) = 6

Then the slope-intercept equation is ...

  y = mx +b

  y = 1/2x +6

show that the line x-y+2=0 and the line joining the points (4,6) and (10,12) are parallel to each other

Answers

x-y+2=0

-y= -x-2

y=x+2

In order for the other line to be parallel, the slope has to be the same.

(12-6)/(10-4)= 6/6= 1

Both slopes are the same, meaning it is parallel.

how many wall are there in your room? what are the shape of the floor and ceiling in your room ? how can you find the area of each shape?prepare the answer. present the conclusion in the form of report. plz answer the question in right.​how many wall are there in your room? what are the shape of the floor and ceiling in your room ? how can you find the area of each shape?prepare the answer. present the conclusion in the form of report. plz answer the question in right. plz answer the question steps by step.​

Answers

Answer:

4 walls in my room. The shape of my room is square and my ceiling in square. By looking at it and measuring it. Thats how I found my answer.

I believe this is correct if it is can you mark brainliest? Hope I helped!!!! :)

Answer:

8 walls etc....

Step-by-step explanation:

Given the directrix of y = 4 and focus of (0, 2), which is the equation of the parabola?

Answers

Answer:

The equation of the parabola is,

x²+4y-12=0

A rectangle has an area of 616 m² and a width of 22m. What is its length?

Answers

Answer:

l=28m

w Width

22

m

A Area

616

Using the formula

A=wl

Solving forl

l=A

w=616

22=28m

hope this will help you

make me brainliest

Answer:

Solve for length

l=28m

W= Width

22

m

A= Area

616

Using the formula

A=wl

Solving formula

l=A

W=616

22=28m

gordan is twice as old as tony was when gordan was as old as tony is now. combined age of gordan and tony is 112 years. how old are gordan and tony now?​

Answers

gordan is 67 and Tony is 45 years old

Answer:

Answer

Tony:48

Gordan :64

Step-by-step explanation:

[tex]\begin{array}{c|c|c}Age&Gordon&Tony\\------------------&-------&-------\\now&g&t\\when\ gordan\ was\ as\ old\ as\ tony\ is\ now&t(=g-g+t)&t-g+t=2t-g\\\end{array}\\\\\\\\\left\{\begin{array}{ccc}g&=&2*(2t-g)\\g+t&=&112\\\end {array}\right.\\\\\\\left\{\begin{array}{ccc}3g&=&4t\\g+t&=&112\\\end {array}\right.\\\\\\\left\{\begin{array}{ccc}g&=&\dfrac{4}{3}\\\dfrac{7}{3} t&=&112\\\end {array}\right.\\\\\\\left\{\begin{array}{ccc}t&=&48\\g&=&64\\\end {array}\right.\\[/tex]

Proof:

16 years ago, Gordan was 48 and Tony 32.

64=2*32

64+48=112

PLSSS HELP IM STRUGGLING SO HARD !!! ———————

Answers

Answer:

C)

Step-by-step explanation:

Just see the length of the R line, A and B are almost the same large when you add them.

Answer:

C).

Step-by-step explanation:

Because it is the largest side in that specific triangle

Please help ASAP please help me

Answers

9514 1404 393

Answer:

  C)  12 cm

Step-by-step explanation:

In a 30°-60°-90° triangle, the ratios of side lengths are ...

  1 : √3 : 2

This means the hypotenuse (AC) is 2/√3 times the length of the long side (AB).

  (10 cm)(2/√3) = 20/√3 cm ≈ 11.55 cm

Rounded to the nearest cm, the length of AC is 12 cm.

A service station has both self-service and full-service islands. On each island, there is a single regular unleaded pump with two hoses. Let X denote the number of hoses being used on the self-service island at a particular time, and let Y denote the number of hoses on the full-service island in use at that time. The joint pmf of X and Y appears in the accompanying tabulation. y p(x, y) 0 1 2 x 0 0.10 0.03 0.02 1 0.06 0.20 0.07 2 0.05 0.14 0.33 (a) What is P(X

Answers

Answer:

[tex]P(x = 1) = 0.33[/tex]

[tex]P(y = 2) = 0.42[/tex]

Step-by-step explanation:

Given

                    y

x [tex]\begin{array}{cccc}P(x,y) & {0} & {1} & {2} & {0} & {0.10} & {0.03} & {0.02} & {1} & {0.06} & {0.20} & {0.07} & {2} & {0.05} & {0.14} & {0.33}\ \end{array}[/tex]

Solving (a)

[tex]P(x = 1)[/tex]

To do this, we simply add all data where x = 1

So, we have:

[tex]P(x = 1) = P(x=1|y=0) + P(x=1|y=1) + P(x=1|y=2)[/tex]

[tex]P(x = 1) = 0.06 + 0.20 + 0.07[/tex]

[tex]P(x = 1) = 0.33[/tex]

Solving (b)

[tex]P(y = 2)[/tex]

To do this, we simply add all data where y = 2

So, we have:

[tex]P(y = 2) = P(x=0|y=2) + P(x=1|y=2) + P(x=2|y=2)[/tex]

[tex]P(y = 2) = 0.02 + 0.07 + 0.33[/tex]

[tex]P(y = 2) = 0.42[/tex]

please give me correct answer​

Answers

Answer:

answer of question number 1 is 2400, 2880, 3600 respectively.

answer of question number 2 is 1384 and 1680.

Step-by-step explanation:

100×24=2400

120×24=2880

150×24=3600

692×2=1384

420×4=1680

Help me please guys thanks

Answers

Answer:

A is correct

Step-by-step explanation:

Tenisha solved the equation below by graphing a system of equations.
log35x = log (2x+8)
Which point approximates the solution for Tenisha's system of equations?
0 (0.9, 0.8)
O (1.0, 1.4)
O (2.3, 1.1)
O (2.7, 13.3)

Answers

Answer:

Option B.)

Step-by-step explanation:

Just took the test and got 100% :]

The system of logarithmic equation is graphed and the point of intersection of the equation is log₃ ( 5x ) = log₅ ( 2x + 8 ) is A ( 1.0 , 1.4 )

What is Equation of Graph of Polynomials?

Graphs behave differently at various x-intercepts. Sometimes the graph will cross over the x-axis at an intercept. Other times the graph will touch the x-axis and bounce off.

Identify the even and odd multiplicities of the polynomial functions' zeros.

Using end behavior, turning points, intercepts, and the Intermediate Value Theorem, plot the graph of a polynomial function.

The graphs cross or are tangent to the x-axis at these x-values for zeros with even multiplicities. The graphs cross or intersect the x-axis at these x-values for zeros with odd multiplicities

Given data ,

Let the solution to the logarithmic equation be represented as A

Now , the value of A is

log₃ ( 5x ) = log₅ ( 2x + 8 )

On simplifying , we get

log₃ ( 5x ) = log₁₀ ( 5x ) / log₁₀ ( 3 )

log₅ ( 2x + 8 ) = log₁₀ ( 2x + 8 ) / log₁₀ ( 5 )

Substituting the logarithmic quantities , we get

log₁₀ ( 5x ) / log₁₀ ( 3 ) = log₁₀ ( 2x + 8 ) / log₁₀ ( 5 )

On cross multiplying , we get

log₁₀ ( 5x ) / log₁₀ ( 2x + 8 ) = log₁₀ ( 3 ) / log₁₀ ( 5 )

( 5x ) / ( 2x + 8 ) = 3/5

On cross multiplying , we get

25x = 6x + 24

Subtracting 6x on both sides , we get

19x = 24

Divide by 19 on both sides , we get

x = 1.26

Therefore , the approximate values of the function on graphing is A ( 1.0 , 1.4 )

Hence , the solution of function from graphing is A ( 1.0 , 1.4 )

To learn more about equation of graph of polynomials click :

https://brainly.com/question/16957172

#SPJ7

The graph shows the distribution of the number of text messages young adults send per day. The distribution is approximately Normal, with a mean of 128 messages and a standard deviation of 30 messages.

A graph titled daily text messaging has number of text on the x-axis, going from 8 to 248 in increments of 30. Data is distributed normally. The highest point of the curve is at 128.

What percentage of young adults send between 68 and 158 text messages per day?

34%
47.5%
81.5%
95%

Answers

Answer:  C) 81.5%

This value is approximate.

====================================================

Explanation:

We have a normal distribution with these parameters

mu = 128 = population meansigma = 30 = population standard deviation

The goal is to find the area under the curve from x = 68 to x = 158, where x is the number of text messages sent per day. So effectively, we want to find P(68 < x < 158).

Let's convert the score x = 68 to its corresponding z score

z = (x-mu)/sigma

z = (68-128)/30

z = -60/30

z = -2

This tells us that the score x = 68 is exactly two standard deviations below the mean mu = 128.

Repeat for x = 158

z = (x-mu)/sigma

z = (158-128)/30

z = 30/30

z = 1

This value is exactly one standard deviation above the mean

-------------------------------------------

The problem of finding P(68 < x < 158) can be rephrased into P(-2 < z < 1)

We do this because we can then use the Empirical rule as shown in the diagram below.

We'll focus on the regions between z = -2 and z = 1. This consists of the blue 13.5% on the left, and the two pink 34% portions. So we will say 13.5% + 34% + 34% = 81.5%

Approximately 81.5% of the the population sends between 68 and 158 text messages per day. This value is approximate because the percentages listed in the Empirical rule below are approximate.

Answer:

C. 81.5%

Step-by-step explanation:

Which of the following sets are equal to {x|x < 9 and x> 2}

{3,4,5,6,7,8}

{2,3,4,5,6,7,8,9}

{}

{2,3,4,5,6,7}

Answers

Answer:

{3, 4, 5, 6, 7, 8}

Step-by-step explanation:

{x|x < 9 and x > 2}= {3, 4, 5, 6, 7, 8}

[tex]\tt{ \green{P} \orange{s} \red{y} \blue{x} \pink{c} \purple{h} \green{i} e}[/tex]

Integers are sometimes whole numbers

true or false

Answers

Answer:

True

Step-by-step explanation:

Integers are always whole numbers

negative, 0, positive:: whole numbers

Tay-Sachs disease is a genetic disorder that is usually fatal in young children. If both parents are carriers of the disease, the probability that their offspring will develop the disease is approximately 0.25. Suppose that a husband and wife are both carriers and that they have four children. If the outcomes of the four pregnancies are mutually independent, what are the probabilities of the following events?
a. All three children will develop Tay–Sachs disease.
b. Only one child will develop Tay–Sachs disease.
c. The third child will develop Tay–Sachs disease, given that the first two did not.

Answers

Lo siento mucho, necesito los puntos porque estoy en una prueba.

Find the length of BC

Answers

Since this is a right triangle, we can use one of the three main trigonometric functions: sine, cosine or tangent.

Remember: SOH-CAH-TOA

Looking from the given angle, we want to find the opposite side and we know the hypotenuse. Therefore, we should use sine.

sin(51) = BC / 58

BC = 58 x sin(51)

BC = 45.1 units

Hope this helps!

Step-by-step explanation:

Hey there!

From the above given figure;

Angle CAB = 51°

AB = 58

Taking Angle CAB as reference angle we get;

Perpendicular (p) = BC= ?

Hypotenuse (h) = 58

Now;

Taking the ratio of sin we get;

[tex] \sin( \alpha ) = \frac{p}{h} [/tex]

[tex] \sin(51) = \frac{bc}{58} [/tex]

Simplify it;

0.7771459*58 = BC

Therefore, BC = 45.0744.

Hope it helps!

Put the following equation of a line into slope-intercept form, simplifying all
fractions.
18x + 3y = -18

Answers

Answer:

y= -6x-6, I think, hope it helped

Step-by-step explanation:

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