In a large section of a statistics​ class, the points for the final exam are normally​ distributed, with a mean of 71 and a standard deviation of 7. Grades are assigned such that the top​ 10% receive​ A's, the next​ 20% received​ B's, the middle​ 40% receive​ C's, the next​ 20% receive​ D's, and the bottom​ 10% receive​ F's. Find the lowest score on the final exam that would qualify a student for an​ A, a​ B, a​ C, and a D.

Answers

Answer 1

Answer:

The lowest score on the final exam that would qualify a student for an​ A is 80.

The lowest score on the final exam that would qualify a student for a B is 74.68.

The lowest score on the final exam that would qualify a student for a C is 67.33.

The lowest score on the final exam that would qualify a student for a​ D is 62.

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.

Mean of 71 and a standard deviation of 7.

This means that [tex]\mu = 71, \sigma = 7[/tex]

Grades are assigned such that the top​ 10% receive​ A's, the next​ 20% received​ B's, the middle​ 40% receive​ C's, the next​ 20% receive​ D's, and the bottom​ 10% receive​ F's.

This means that:

90th percentile and above: A

70th percentile and below 90th: B

30th percentile to the 70th percentile: C

10th percentile to the 30th: D

Lowest score for an A:

Top 10% receive A, which means that the lowest score that would qualify a student for an A is the 100 - 10 = 90th percentile, which is X when Z has a pvalue of 0.9, so X when Z = 1.28.

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

[tex]1.28 = \frac{X - 71}{7}[/tex]

[tex]X - 71 = 7*1.28[/tex]

[tex]X = 80[/tex]

The lowest score on the final exam that would qualify a student for an​ A is 80.

Lowest score for a B:

70th percentile, which is X when Z has a pvalue of 0.7, so X when Z = 0.525.

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

[tex]0.525 = \frac{X - 71}{7}[/tex]

[tex]X - 71 = 7*0.525[/tex]

[tex]X = 74.68[/tex]

The lowest score on the final exam that would qualify a student for a B is 74.68.

Lowest score for a C:

30th percentile, which is X when Z has a pvalue of 0.3, so X when Z = -0.525.

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

[tex]-0.525 = \frac{X - 71}{7}[/tex]

[tex]X - 71 = 7*(-0.525)[/tex]

[tex]X = 67.33[/tex]

The lowest score on the final exam that would qualify a student for a C is 67.33.

Lowest score for a D:

10th percentile, which is X when Z has a pvalue of 0.1, so X when Z = -1.28.

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

[tex]-1.28 = \frac{X - 71}{7}[/tex]

[tex]X - 71 = 7*(-1.28)[/tex]

[tex]X = 62[/tex]

The lowest score on the final exam that would qualify a student for a​ D is 62.


Related Questions

Ava runs at a constant speed of 3.4 meters per second for 1/2 hour. Then, she walks at a rate of 1.5 meters per second for 1/2 hours. How far did Ava run and walk in 60 minutes?

Answers

Ava ran and walked 8,820m in 60 minutes.

Laura received a $80 gift card for a coffee store. She used it in buying some coffee that cost $7.96 per pound. After buying the coffee, she had $56.13
left on her card. How many pounds of coffee did she buy?

Answers

Answer:

Step-by-step explanation:

Hi.

I can help.

First what we want to do is take what she had before spending any money and then take what she had after.

So :

$80.00

and

$56.13

Now to find how much she spent we can subtract these two numbers like so :

80.00 - 56.13

=

23.87

So now we know she spent a total of $23.87 on coffee in pounds.

Now if each pound of coffee costs $7.96 we can divide this into how much she spent $23.87 to find the total amount of pounds she bought for $7.96.

So:

23.87 / 7.96

=

About 3

She bought 3 pounds of coffee.

Hope this helps,

Have a great weekend

(4-√2)(4+ √2) how do i solve it¿

Answers

Answer:

Step-by-step explanation:

[tex]4(4)+4\sqrt{2}-4\sqrt{2}-\sqrt{2}\sqrt{2}=16-2=14[/tex]

pre-algebra question help

Answers

Step-by-step explanation:

step 1. 15n + 75v = 330, n - v = 2.

step 2. This is a system. solve the system.

step 3. multiply the 2nd equation by 15 and subtract from the 1st equation.

step 4. 90v = 300. v = 10/3

step 5. n - 10/3 = 2. n = 16/3.

step 6. new = 10/3, vintage = 16/3.

step 7. either they sell games in thirds or the question has a mistake.

Gold has a density of 19.3 g/mL. What is the mass of a 7.5 mL sample of gold?

Answers

Answer:

144.75 g

Step-by-step explanation:

19.3x7.5 = 144.75

Math To Do, i-Ready + Liready.com/student/dashboard/home iReady Understand Fractions as Division - Instruction - Level E Finn, Rita, and Marcus have 2 blueberry granola bars to share equally. Finn Rita Marcus​

Answers

Answer:

21

Step-by-step explanation:

21

2) A recent survey of 2625 elementary school children found that 28% of the children could be classified obese.

Answers

The answer is 735 kids could be classified as obese
Hope this helps :)

help me do this please!!!

Answers

Answer:

Step-by-step explanation:

ok soo....

the area of the one like higher up would be 42

and then the area of the one like landscape would be 48

and then the area of like the box they make in the middle is 30

so ya i hope this helped

2 1/4x + (4 1/3x − 7 4/5 ) ÷ 2 3/5

Answers

Answer:

1/4*(9x+130x-234/35

Step-by-step explanation:

get photomath

A person has 30 Rap songs, 25 R&B songs, 30 Alternative songs, 22 Pop songs, 15 Country songs, and 28 Hip Hop songs stored on an MP3 player (a total of 150 songs). If the person set the MP3 player to random shuffle, what are the odds of the first song being played being a Country song?
A) .1
B) .2
C) .3
D) .4

Answers

Answer:

10% or 1/10 chance

Step-by-step explanation:

The chances of playing a country song first try is 15/150 or 1/10. There is a 10% chance of playing a country song on the first try.

In a housing project there are 180 households in which English is usually spoken, 80 in which Spanish is usually spoken, and 40 in which the language is other than English or Spanish. A researcher approaches a house at random to conduct an interview. What is the chance that the usual language in that household will NOT be English

Answers

Answer:

The chance that the usual language in that household will NOT be English = 0.4

Step-by-step explanation:

As given ,

Total households in which languages spoken is English = 180

Total households in which languages spoken is Spanish = 80

Total households in which languages spoken is other than English or Spanish  = 40

So,

Total households = 180 + 80 + 40 = 300

Now,

Household in which English language is not spoken = 80 + 40 = 120

So,

The chances that the usual language in that household will NOT be English = [tex]\frac{120}{300} = \frac{12}{30} = \frac{4}{10} = 0.4[/tex]

∴ we get

The chance that the usual language in that household will NOT be English = 0.4

Which expression is equivalent to 3 to the power of 3 x 6 to the power of 3 x 2 to the power of three

Answers

Answer:

Step-by-step explanation:

3³×6³×2³ = 3³×2³×6³ = (3×2)³×6³ = 6³×6³ = 6⁶

find the equation of the line with the coordinates of (-5,-2) and (5,3)​

Answers

Answer

x - 2y = -1.

Step-by-step explanation:

Slope = (3 - (-2)) / (5 - (-5))

= 5/10

= 1/2

Using the point-slope form of a straight line equation:

y - y1 = m(x - x1)

Here m = 1/2 and (x1, y1) = (5, 3):

y - 3 = 1/2(x - 5)

y - 3 = 1/2x - 5/2

y = 1/2x  - 5/2 + 6/2

y = 1/2x +  1/2

Removing the fractions:

2y = x  + 1

in standard form this is

x - 2y = -1

Jacob and Adam are selling pies for a school fundraiser. Customers can buy cherry pies and blackberry pies. Jacob sold 1 cherry pie and 1 blackberry pie for a total of $35. Adam sold 12 cherry pies and 9 blackberry pies for a total of $360. Find the cost each of one cherry pie and one blackberry pie. Write as an ordered pair. Ex: (cherry pie, blackberry pie)

Answers

Answer:

Step-by-step explanation:

c and b are the number of cherry and blackberry sold.

1c + 1b = 35

b = 35-c

12c +  9b = 360

12c + 9(35-c) = 360

3c = 45

c = 15

b = 35-c = 20

$15 for one cherry pie, $20 for one blackberry pie.

How to write and graph at least 10 on a number line​

Answers

Answer:

hope it helps you (:

Step-by-step explanation:

Graphing an inequality on a number line, is very similar to graphing a number. For instance, look at the top number line x = 3. We just put a little dot where the '3' is, right?

Now an inequality uses a greater than, less than symbol, and all that we have to do to graph an inequality is find the the number, '3' in this case and color in everything above or below it.

Just remember

if the symbol is (≥ or ≤) then you fill in the dot, like the top two examples in the graph below

if the symbol is (> or <) then you do not fill in the dot like the bottom two examples in the graph below

To better understand how to graph inequalities, look at the examples below or experiment with the grapher that is immediately below.

If significant digits are used to compute the product of 0.105 and 1000.2000, how many significant digits are there in the answer?

A. 0
B. 1
C. 2
D. 3

Answers

Answer:

A is the answer!

Step-by-step explanation:

There are 6 significant digits are in the answer.

What is Multiplication?

To multiply means to add a number to itself a particular number of times. Multiplication can be viewed as a process of repeated addition.

Given that;

Here, significant digits are used to compute the product of 0.105 and 1000.2000,

Now,

Multiplication of 0.105 and 1000.2000 is,

⇒ 0.105 × 1000.2000

⇒ 105.021

Hence, There are 6 significant digits are in the answer.

Learn more about the multiplication visit:

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The Wall Street Journal reported that the median salary for middle-level manager jobs was approximately $85,000 (The Wall Street Journal, August 6, 2013). Suppose that an independent study of middle-level managers employed at companies located in Atlanta, Georgia, was conducted to compare the salaries of managers working at firms in Atlanta to the national average. The following data show the salary, in thousands of dollars, for a 8. sample of 15 middle-level managers.
108 83 106 73 53 85 80 63 67 75 124 55 93 118 77
a. Compute the median salary for the sample of 15 middle-level managers. How does the median for this group compare to the median reported by The Wall Street Journal?
b. Compute the mean annual salary and discuss how and why it differs from the median a. b. computed in part (a).
c. Compute the first and third quartiles.

Answers

Answer:

Median = $80,000 ; Mean = $84,000 ; Q1 = 67,000 ; Q3 = 106,000

Step-by-step explanation:

Given the data :

108 83 106 73 53 85 80 63 67 75 124 55 93 118 77

Reorderd data :

53, 55, 63, 67, 73, 75, 77, 80, 83, 85, 93, 106, 108, 118, 124

The median salary:

1/2(n+1)th term

Sample size, n = 15

1/2 (15 + 1)th term

1/2(16)th term

8th term = 80

Median is $80,000

Median reported by Wall Street Journal approximately $85000

The obtained and reported values are close

The mean annual salary :

ΣX / n = 1260 / 15 = 84

Mean annual salary = $84,000

Mean is the average of all earnings combined, median is the mid value of he data.

First and third quartile :

Q1 = 1/4(n+1)th term

Q1 = 1/4(16)th term

Q1 = 4th term = 67

Third quartile:.

Q3 = 3/4(n+1)th term

Q3 = 3/4(16)th term

Q3 = 12th term = 106

Write an equation of the line that passes through the given points.
(-2,5) and (3,0)

Answers

9514 1404 393

Answer:

  y = -x +3

Step-by-step explanation:

The 2-point form of the equation of a line is useful when 2 points are given.

  y = (y2 -y1)/(x2 -x1)(x -x1) +y1

  y = (0 -5)/(3 -(-2))(x -(-2)) +5

  y = -5/5(x +2) +5

  y = -x +3

Salim had a flock of 300 chickens 15% of which are infected with a virus he plans on taking a SRS of 7 chickens to test for the virus.

Answers

Answer:0.011

Step-by-step explanation:

The probability for exact 4 chickens being infected out of the 7 is ⁷C₄(0.15)⁴(0.85)³. The correct option is (A).

How to find probability using binomial distribution?

The binomial distribution is based on the binomial theorem which can be written as (a + b)ⁿ = ⁿC₀aⁿb⁰ + ⁿC₁aⁿ⁻¹b¹ + ⁿC₂aⁿ⁻²b²+ ....+ ⁿCₙa₀bⁿ.

In order to use in the probability, there should be events independent of each other and the sum of there probabilities is 1.

Given that,

The probability of the infected chicken is 15%.

Which can be written as,

P(infected) = 15%

                  = 15/100

                  = 0.15

Then, the probability of not getting infected chicken is,

P(not infected) = 1 - 0.15

                        = 0.85

The total number of chicken for test = 7.

Now, in order to find the probability of the exact 4 infected chickens, binomial distribution can be used as.

The general expression for binomial distribution is ⁿCₓpˣqⁿ⁻ˣ.

For the given case p = P(infected) and q = P(not infected), n = 7 and x = 4.

Thus, the probability is given as,

P(Exact 4 are infected) = ⁷C₄(0.15)⁴(0.85)³

Hence, the  probability that exactly 4 of the 7 chickens sampled have the virus is  ⁷C₄(0.15)⁴(0.85)³.

To know more about binomial distribution click on,

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The complete question is given as, "Salim has flock of 300 chickens, 15% of which are infected with virus: He plans on taking an SRS of 7 chickens to test for the virus_ Which of the following would find the probability that exactly 4 of the 7 chickens sampled have the virus? Choose answer: 1(0.15) '(0.85)? (0.15)*(0.85)4 300 ` (0.15)'(0.85)3 (0.15)3(0.85)4 (0.15)4(0.85)".

A company makes 150 bags.
43 of the bags have buttons but no zips.
38 of the bags have zips but no buttons.
34 of the bags have neither zips nor buttons.
How many bags have buttons on them?

Answers

Answer:

Should be 43

Step-by-step explanation:

There are only 43 bags that actually have buttons from the 3 numbers given.

43 is the correct answer

Help me pls I’ll give brainliest

Answers

Answer:

is there another number, if so what is it?

Answer:

25%

Step-by-step explanation:

Look at pic plz help

Answers

Answer:

Mochi

Step-by-step explanation:

Mochi

Each week theres a increase of 4 in Mochi's weight. So you will add 4 twice to get to the 5th week.

4th week : 17

5th week : 21

Kappa

In 4 weeks Kappa weighed 14, which is less that Mochi at the pace Kappa is going at.

on the 3rd week Kappa weighed 11

and 2nd week Kappa weighed 5

and 1st week Kappa weighed 3

Looking at the graph, we can give a rough estimate on the 5th week it's going to be 16 or 17 either way making Mochi heavier.

An ______________ is an equation that is true for all values of the variable and has infinitely many solutions.

Answers

Maybe it’s in ur vocab math pages it’s there for me

simplify (-4/5)^9/(-4/5)^10​

Answers

Answer:

- 5/4

Step-by-step explanation:

exact form:-5/4

decimal form:-1.25

mixed number form: -1 1/4

Find the range of the function f(x) = 3x - 8
if the domain is {-4, 2, 7).

Answers

Answer:

f(-4)=3(-4)-8

f(-4)=-12-8

f(-4)=-20

f(2)=3(2)-8

f(2)=6-8

f(2)=-2

f(7)=3(7)-8

f(7)=21-8

f(7)=13

R=(-20, -2, 13)

The range of the function when  f(x) = 3x - 8 and the domain is {-4, 2, 7) is (-20, -2, 13).

Calculation of the range:

Since

f(-4)=3(-4)-8

f(-4)=-12-8

f(-4)=-20

Now

f(2)=3(2)-8

f(2)=6-8

f(2)=-2

Now

f(7)=3(7)-8

f(7)=21-8

f(7)=13

So,

R=(-20, -2, 13)

hence, The range of the function when  f(x) = 3x - 8 and the domain is {-4, 2, 7) is (-20, -2, 13).

learn more about range here; https://brainly.com/question/13455383

The blood platelet counts of a group of women have a​ bell-shaped distribution with a mean of 246.8 and a standard deviation of 67.2. ​(All units are 1000 ​cells/μ​L.) Using the empirical​ rule, find each approximate percentage below. a. What is the approximate percentage of women with platelet counts within 1 standard deviation of the​ mean, or between 179.6 and 314.0​? b. What is the approximate percentage of women with platelet counts between 45.2 and 448.4​?

Answers

Answer:

a. 68%

b. 99.7%.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

68% of the measures are within 1 standard deviation of the mean.

95% of the measures are within 2 standard deviation of the mean.

99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean = 246.8

Standard deviation = 67.2

a. What is the approximate percentage of women with platelet counts within 1 standard deviation of the​ mean, or between 179.6 and 314.0​?

By the Empirical Rule, approximately 68%.

b. What is the approximate percentage of women with platelet counts between 45.2 and 448.4​?

45.2 = 246.8 - 3*67.2

448.4 = 246.8 + 3*67.2

Within 3 standard deviations of the mean, so approximately 99.7%.

1/2+p=-3


Pleaseee help

Answers

Answer:

The answer is p= -7/2

Step-by-step explanation:

Move all terms not containing  p  to the right side of the equation.

Hoped this helped!

brainly, please?

need some help please

Answers

Answer:

A

Step-by-step explanation:

y= 6x

Plug and chug the function.

Can some one please help me solve this inequality?
x − 3 ≤ 5 or x + 4 ≥ 14

Answers

Answer:

Just look down lol

Step-by-step explanation:

Anyways, what you would have to do on both sides is try to isolate x on each side, so for the first inequality, you would add 3 on both sides, x[tex]\leq[/tex]8, and for the other equation you would subtract 4 on both sides, so x[tex]\geq[/tex]10

I actually hope this helps

If student D can solve 60% of multiple choice questions and Student B can solve 51% of the multiple choice questions and Student C can solve 57%. The students are unaware of each other.
a) At least one can be solved
b) Probability at most one of them can be solved
c) Probability that neither of them can be solved
d) Exactly two them can be solved

Answers

Do you know answer or not please give me answer
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