The scores for a particular examination are normally distributed with a mean of 68.5% and a standard deviation of 8.2%. What is the probability that a student who wrote the examination had a mark between 80% and 100%? Give your answer to the nearest hundredth.

Answers

Answer 1

Answer:

[tex]P(80/100<x<100/100)=0.08[/tex]

Step-by-step explanation:

We are given that

Mean,[tex]\mu=68.5[/tex]%=68.5/100

Standard deviation, [tex]\sigma=8.2[/tex]%=8.2/100

We have to find the probability that a student who wrote the examination had a mark between 80% and 100%.

[tex]P(80/100<x<100/100)=P(\frac{80/100-68.5/100}{8.2/100}<\frac{x-\mu}{\sigma}<\frac{100/100-68.5/100}{8.2/100})[/tex]

[tex]P(80/100<x<100/100)=P(1.40<Z<3.84)[/tex]

We know that

[tex]P(a<Z<b)=P(Z<b)-P(Z<a)[/tex]

Using the formula

[tex]P(80/100<x<100/100)=P(Z<3.84)-P(Z<1.40)[/tex]

[tex]P(80/100<x<100/100)=0.99994-0.91924[/tex]

[tex]P(80/100<x<100/100)=0.0807\approx 0.08[/tex]


Related Questions

What is the mean of the following list of extra credit points earned on a statistics test?
10,8,18,17,7

Answers

Answer:

12

Step-by-step explanation:

Given the data :

X : 10,8,18,17,7

The mean value of scores obtained can be obtained thus :

Mean = ΣX / n

n = sample size = 5

Mean = ΣX / n = (10+8+18+17+7) / 5

Mean = 60 / 5 = 12

what is factorization of the trinomial below? -x2+2x+48

Answers

Answer:

-(x+6) (x-8)

Step-by-step explanation:

-(x^2-2x-48)

two values the multiply to get 48 and the difference of those two numbers gives you -2.

6,-8

6 x -8 =-48

6-8=-2

In this case we factored out the negative so leave it outside

-(x+6) (x-8)

Answer:

-1(x-8)(x+6) is the answer just took the test

Step-by-step explanation:

Explain how the given graph is deceptive.

Complete the statements based on the bar graph.

By not starting the horizontal axis at 0, the
bar appears to be about one-fourth the height of the Pecan bar. The
bar appears to be about one-half the height of the Pecan bar. The
bar appears to be less than one-half the height of the Pecan bar. This misleads the viewer to
the number of each type of nut used

Ans:

Pine Nut

Walnut

Almond

Understimate

Answers

Answer:

In the picture below.

Step-by-step explanation:

From the commenter and answer above, confirmed on edge 2022.

. Using the identity (a + b)² = (a² + 2ab + b²), evaluate 112²



Answers

[tex]\\ \sf\longmapsto 112^2[/tex]

[tex]\\ \sf\longmapsto (100+12)^2[/tex]

[tex]\\ \sf\longmapsto 100^2+2(100)(12)+12^2[/tex]

[tex]\\ \sf\longmapsto 10000+2400+144[/tex]

[tex]\\ \sf\longmapsto 12400+144[/tex]

[tex]\\ \sf\longmapsto 12544[/tex]

112²

Using Identity

(a + b)² = (a² + 2ab + b²)

Solution

⇛112²

⇛(100 + 12)²

⇛(100)² + 2 × 100 × 12 + (12)²

⇛10000 + 2400 + 144

⇛12400 + 144

⇛12544

Last year at a certain high school, there were 56 boys on the honor roll and 150 girls on the honor roll. This year, the number of boys on the honor roll decreased by 25% and the number of girls on the honor roll decreased by 12%. By what percentage did the total number of students on the honor roll decrease?

Answers

Answer:

15.534% decrease

Step-by-step explanation:

Find the new number of boys and girls on the honor roll:

56(0.75) = 42 boys

150(0.88) = 132 girls

Find the new total number of students on the honor roll:

42 + 132 = 174

Find the percent decrease by dividing the difference in the number of students by the original number.

There were originally 206 total students on the honor roll. Find the difference:

206 - 174 = 32

Divide this by the original amount:

32/206

= 0.15534

So, the number of students on the honor roll decreased by approximately 15.534%

Which expression is equivalent to
-32 3/5
-8
-3/325
3/325
1/8

Answers

Answer:

[tex]-32^\frac{3}{5} = -8[/tex]

Step-by-step explanation:

Given

[tex]-32^\frac{3}{5}[/tex]

Required

The equivalent expression

We have:

[tex]-32^\frac{3}{5}[/tex]

Rewrite as:

[tex]-32^\frac{3}{5} = (-32)^\frac{3}{5}[/tex]

Expand

[tex]-32^\frac{3}{5} = (-2^5)^\frac{3}{5}[/tex]

Remove bracket

[tex]-32^\frac{3}{5} = -2^\frac{5*3}{5}[/tex]

[tex]-32^\frac{3}{5} = -2^3[/tex]

[tex]-32^\frac{3}{5} = -8[/tex]

For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding. A random sample of 5240 permanent dwellings on an entire reservation showed that 1613 were traditional hogans.
(a) Let p be the proportion of all permanent dwellings on the entire reservation that are traditional hogans. Find a point estimate for p. (Round your answer to four decimal places.)
(b) Find a 99% confidence interval for p. (Round your answer to three decimal places.) What is the lower limit? What is the upper limit?

Answers

Answer:

Step-by-step explanation:

point est. 0.307824427

99% 2.58

Confidence Interval - "P" values  

(0.2914 , 0.3243 )  

The curve y=2x^3+ax^2+bx-30 has a stationary point when x=3. The curve passes through the point (4,2).

(A) Find the value of a and the value of b.

#secondderivative #stationarypoints


Answers

A stationary point at x = 3 means the derivative dy/dx = 0 at that point. Differentiating, we have

dy/dx = 6x ² + 2ax + b

and so when x = 3,

0 = 54 + 6a + b

or

6a + b = -54 … … … [eq1]

The curve passes through the point (4, 2), which is to say y = 2 when x = 4. So we also have

2 = 128 + 16a + 4b - 30

or

16a + 4b = -96

4a + b = -24 … … … [eq2]

Eliminate b by subtracting [eq2] from [eq1] and solve for a, then for b :

(6a + b) - (4a + b) = -54 - (-24)

2a = -30

a = -15   ===>   b = 96

Select the statement that best justifies the conclusion based on the given information.

a. Definition of bisector.
b. Definition of midpoint.
c. If two lines intersect, then their intersection is exactly one point.
d. Through any two different points, exactly one line exists.

Answers

9514 1404 393

Answer:

  a. Definition of bisector.

Step-by-step explanation:

Line l is a line through the midpoint M. We can conclude it is a bisector, because, by definition, a bisector is a line through the midpoint.

The conclusion is justified by the definition of a bisector.

"What mathematical ideas are you curious to know more about as a result of takingthis class? Give one example of a question about the material that you'd like to explorefurther, and describe why this is an interesting question to you."

Answers

One mathematical idea I've always been curious about is "integration and derivation".

Integration is about assimilating different variables. Derivation is a mathematical process whereby a result is gotten from some initial assumptions.

Integration is used everyday in different aspects of our lives. For example, if a person is travelling from let's say point A to point B, the speed used by the person might vary but through integration, one can easily get the accurate speed.

Through the division of equations into smaller bits, once can use integration to get the answer that one seeks. Architect can use integration in building the right structures at the exact places where the structures fits.

Likewise derivatives can be used by businesses in assessing whether a profit or loss will be made for a particular transaction or sale of product.

You can read more on:

https://brainly.com/question/14295614

An article is marked to sell at a gain of 10%. If it be sold for Rs. 7.50 less there would be loss of 5%, find the cost price. ​

Answers

Answer:

750,. is answer

I hope it helps

The point A(−8,−4) is reflected over the origin and its image is point B. What are the coordinates of point b?

Answers

9514 1404 393

Answer:

  B(8, 4)

Step-by-step explanation:

Reflection across the origin negates both coordinate values.

  (x, y) ⇒ (-x, -y) . . . . . reflection across the origin

  A(-8, -4) ⇒ B(8, 4)

A publisher reports that 54% of their readers own a personal computer. A marketing executive wants to test the claim that the percentage is actually different from the reported percentage. A random sample of 200 found that 44% of the readers owned a personal computer. Is there sufficient evidence at the 0.10 level to support the executive's claim

Answers

The null and alternate hypotheses are

H0 : u = 0.44  vs   Ha: u > 0.44

Null hypothesis: 44% of readers own a personal computer.

Alternate Hypothesis : greater than 44% of readers own a personal computer.

This is one tailed test and the critical region for this one tailed test for the significance level 0.1 is  Z >  ±1.28

The given values are

p1= 0.54 , p2= 0.44 ; q2= 1-p2= 0.56

Using z test

Z = p1-p2/√p2(1-p2)/n

Z= 0.54-0.44/ √0.44*0.56/200

z= =0.1/ 0.03509

z=  2.849

Since the calculated value of Z=  2.849 is greater than Z= 1.28  reject the null hypothesis therefore there is sufficient evidence to support the executive's claim.

Null hypothesis is rejected

There is sufficient evidence to support the executive's claim at 0.10 significance level.

https://brainly.com/question/2642983

Which equation describes this graph?

Answers

Step-by-step explanation:

The graph clearly has a positive slope. So Answer D couldn't be correct. Next: the y-intercept of this line is (0, -2), so b in the formula y = mx÷ b must be -2.

Therefore the correct equation of this line is

y = x - 2 (choice a)

i need help ON THIS PLS

Answers

Answer:

No, because the ratio of pay to hours is not the same for each pair of value.

AM and CM
BM and BM
AB and CB

Answers

These are variables on your graph

Oak street and elm street run parallel to each other. When main street intersects them, it forms exterior 8, measuring 60. What is the measure of 1?

Answers

Answer:

0 is the answer measure 1

An insurance company offers its policyholders a number of different premium payment options. For a randomly selected policyholder, let X 5 the number of months between successive payments. The cdf of X is as follows:

0 x<1
0.30 1< x <3
F(x)= 0.40 3< x <4
0.45 4< x <6
0.60 6< x <12
1 12< x

Required:
a. What is the pmf of x?
b. Using just the cdf, compute P(3< x <6)and P(4< x)

Answers

Answer:

(a)

[tex]\begin{array}{cccccc}x & {1} & {3} & {4} & {6} & {12} \ \\ P(x) & {0.30} & {0.10} & {0.05} & {0.15} & {0.40} \ \end{array}[/tex]

(b)

[tex]P(3 \le x \le 6) = 0.30[/tex]

[tex]P(4 \le x)=0.60[/tex]

Step-by-step explanation:

Given

[tex]F(x) = \left[\begin{array}{ccc}0& x<1 &\\0.30&1 \le x<3 &\\0.40&3 \le x < 4& &0.45 &4 \le x<6 &\\0.60 & 6 \le x < 12 & & 1 & 12 \le x\end{array}\right[/tex]

Solving (a): The pmf

This means that we list out the probability of each value of x.

To do this, we simply subtract the current probability value from the next.

So, we have:

[tex]\begin{array}{cccccc}x & {1} & {3} & {4} & {6} & {12} \ \\ P(x) & {0.30} & {0.10} & {0.05} & {0.15} & {0.40} \ \end{array}[/tex]

The calculation is as follows:

[tex]0.30 - 0 = 0.30[/tex]

[tex]0.40 - 0.30 = 0.10[/tex]

[tex]0.45 - 0.40 = 0.05[/tex]

[tex]0.60 - 0.45 = 0.15[/tex]

[tex]1 - 0.60 = 0.40[/tex]

The x values are gotten by considering where the equality sign is in each range.

[tex]1 \le x < 3[/tex] means [tex]x = 1[/tex]

[tex]3 \le x < 4[/tex] means [tex]x = 3[/tex]

[tex]4 \le x < 6[/tex] means [tex]x=4[/tex]

[tex]6 \le x < 12[/tex] means [tex]x = 6[/tex]

[tex]12 \le x[/tex] means [tex]x = 12[/tex]

Solving (b):

[tex](i)\ P(3 \le x \le 6)[/tex]

This is calculated as:

[tex]P(3 \le x \le 6) = F(6) - F(3-)[/tex]

From the given function

[tex]F(6)= 0.60[/tex]

[tex]F(3-) = F(1) = 0.30[/tex]

So:

[tex]P(3 \le x \le 6) = 0.60 - 0.30[/tex]

[tex]P(3 \le x \le 6) = 0.30[/tex]

[tex](ii)\ P(4 \le x)[/tex]

This is calculated as:

[tex]P(4 \le x)=1 - F(4-)[/tex]

[tex]P(4 \le x)=1 - F(3)[/tex]

[tex]P(4 \le x)=1 - 0.40[/tex]

[tex]P(4 \le x)=0.60[/tex]

Let two events A and B be independent. Knowing P(A)=0.8 and P(A+B)=0.93. Calculate the probability P(B).

Answers

Answer:

Hello,

P(B)=0.65

Step-by-step explanation:

If P(A+B) means P(A∪B)=0.93 then you may read below.

Let's say x=P(B)

A and B being independent, P(A∩B)=P(A)*P(B)=0.8*x

Since P(A∪B)=P(A)+P(x)-P(A∩B) ,

0.93=0.8+x-0.8*x

0.2*x=0.13

x=0.65

Write an equation and solve it to answer each question. A pile of 55 coins consisting of nickels and dimes is worth $3.90. Find the number of each. I only need the equation plz. WILL MARK BRAINLIEST.

Answers

Answer:

0.05x + 0.1(55 - x) = 3.9

Step-by-step explanation:

There are 55 coins.

Let x = number of nickels.

The number of dimes is 55 - x.

The value of a nickel is $0.05, and the value of a dime is $0.10.

The value of x nickels is 0.05x

The value of 55 - x dimes is 0.1(55 - x)

The total value of the coins is 0.05x + 0.1(55 - x)

The total value of the coins is $3.90

0.05x + 0.1(55 - x) = 3.9

Farah is x years old. Ibtisam is 3 years younger than Farah. Muna is twice as old as Ibtisam. Write and expression in terms of x, for
(a) Ibtisam's age,
(b) The sum of their three ages, giving your answer in its simplest form.​

Answers

Answer:

Farah: x

Ibtisam: x-3

Muna: 2(x-3) or 2x-6

Sum of all their ages: 4x-6

Step-by-step explanation:

Farah is x, so we don't need an expression for that.

Ibtisam is 3 years younger than Farah, which means that we need to subtract 3 from Farah, and that would be Ibtisam's age. x-3.

Muna is 2 TIMES Ibtisam's age, so we need to multiply whatever expression taht was used for Ibtisam by 2. Put brackets around the equation with 2 outside: 2(x-3). Solve and you get 4x-6

Now, you have all their ages in expression form, now you need to simplify by adding:

x+x+2x-6

We cannot simplify -6, so we put that aside. Add all the x's and you get 4x, insert the minus 6 at the end:

4x-6

Hope this helps!

--Applepi101

Answer:

a) X -3

b) 4x - 9

Step-by-step explanation:

a) Farah's age is X so Ibtisam will be X - 3 old since he is 3years younger than Farah

b) Farah is X years old

Ibtisam is X - 3 years old

Muna is 2(X -3) since she is 2 times older than Ibtisam.

the sum of Thier ages will be

X + X -3 + 2(x-3)

= 2x - 3 + 2x - 6

= 4x - 9

What information is NOT necessary to find the area of a circle?
a.
pi
c.
diameter
b.
radius
d.
height

Answers

Answer:

D. Height

General Formulas and Concepts:

Geometry

Area of a Circle: A = πr²

r is radius

Step-by-step explanation:

In order to find the area of a circle, we must follow the formula. Out of all the options given, height is not incorporated into the formula.

It wouldn't make sense to use height anyways since it would be 3-dimenional and we're talking 2-dimensional.

∴ our answer is D.

jane drove 50 miles more then her husband jim. the total distance traveled was 230 miles. find the number of miles that each of them traveled. (let jim be x and jane be x+50)

Answers

Answer:

115

Step-by-step explanation:

You divide 230 by 2 cause there are two peoples. I hope that helps :)

If 15% of the customer's total is $22.05, then the customer's total is

Answers

Answer:

$147

Step-by-step explanation:

0.15x = $22.05

Divide both sides by 15

22.05/0.15 = $147

If the nominal rate of interest is 10% per annum and there is quarterly compounding, the effective rate of interest will be: a) 10% per annum b) 10.10 per annum c) 10.25%per annum d) 10.38% per annum​

Answers

9514 1404 393

Answer:

  d) 10.38%

Step-by-step explanation:

The multiplier for four quarters of quarterly compounding is ...

  (1 +10%/4)^4 = 1.025^4 = 1.103812890625

This is about 1 + 10.38%.

The effective rate of interest is about 10.38% per annum.

The blueprints of a house have a scale factor of 30. If one side of the house measures 4 inches on the blueprint, how long is the actual side length (in feet)?

A. 7.5 feet
B.10 feet
C. 90 feet
D. 120 feet

Answers


c. 90 feet is the actual length

If the scale factor is 30, then all you have to do is multiply each measurement by the scale factor. In this case, 4 · 30 = 120.

Bod and coa are _____ angles

Answers

Answer:

opposite angles

Step-by-step explanation:

They are formed in the intersection of lines AD and BD.

Answer:

opposite angles

Step-by-step explanation:

they are formed in the intersection of lines AD and BD. two figures are called similar if they have same shape however have different size.

Find the length represented by x for each pair of similar triangles.
18cm, 9cm, and x
30cm, 15cm, and 25cm

Answers

Answer:

15 cm

Step-by-step explanation:

Since the traingles are similar, we can find the ratio between the side lengths, and it will be the same for each side.

We can use the side length 9 and 15 to find this ratio. 15/9=5/3. So, the ratio of a side length of the larger triangle to the smaller one is 5/3, so our equation becomes 5/3 = 25/x. Use any method you like to find that x=15.

Hope this helped,

~cloud

You are dealt one card from a​ 52-card deck. Find the probability that you are not dealt a heart.

The probability is ___.
​(Type an integer or a fraction. Simplify your​ answer.)

Answers

Answer:

3/4

Step-by-step explanation:

There are 13 hearts in a 52 deck.

52-13=39

39/52=3/4

The probability that you are not dealt a heart from the deck of cards is 3/4.

What is the probability that you are not dealth with a heart?

Probability determines the chances that an event would occur. The probability the event occurs is 1 and the probability that the event does not occur is 0.

The probability that you are not dealth with a heart = 1 - (number of hearts / total number of cards)

1 - 13/52 = 39/52 =  3/4

To learn more about probability, please check: https://brainly.com/question/13234031

A bookkeeper needs to post the cost of the desk and the chair into his records. The cost of the desk is fives times the cost if the chair. The total cost of the desk and the chair is $720, what is the cost of the chair?

Answers

Answer:

120

Step-by-step explanation:

720÷6

why?

becoz 6= 1+5

1 is the cosy of the chair

5 is the cost of the desk

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