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mafiozo [28]
3 years ago
14

an instructor grades on a curve by assuming that grades on a test are normally distributed. If the average grade is 80 and the s

tandard deviation is 8 find the test score for each grade interval if the instructor assigns grades
Mathematics
1 answer:
sweet [91]3 years ago
3 0

Step-by-step explanation:

According to normal distribution curves following a bell curve formula, it is followed that

34% of people will lie between Mean point and one positive standard deviation

34% of people will lie between Mean point and one negative standard deviation

14% of people will lie between Mean point and two positive standard deviation

14% of people will lie between Mean point and two negative standard deviation

2% of people will lie between Mean point and three positive standard deviation

2% of people will lie between Mean point and three negative standard deviation

Now following this principle, we are given that mean score is 80 and standard deviation is 8, hence the interval for grades would be;

Grade A ; Score greater than 96

Grade B : Score greater than 88 and less than or equal to 96

Grade C : Score greater than 80 and less than or equal to 88

Grade D : Score greater than 72 and less than or equal to 80

Grade E : Score greater than 64 and less than or equal to 72

Grade F : Score less than 64

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Two grapefruits and three oranges cost $1.95. Three grapefruits and two oranges cost $2.05.
geniusboy [140]

Answer:

  • one orange costs $0.35  and  one grapefruit costs $0.45

Step-by-step explanation:

<em>let grapefruits be g , let oranges be o</em>

so first equation:

→2g + 3o  = $1.95

→g = ($1.95 - 3o)/2

so second equation:

→ 3g + 2o = $2.05

→ g = ($2.05 - 2o)/3

Solving simultaneously:

→ ($2.05 - 2o)/3 = ($1.95 - 3o)/2

→ 2($2.05 - 2o) = 3($1.95 - 3o)

→ 4.1 - 4o = 5.85 - 9o

→ - 4o + 9o = 5.85 - 4.1

→ 5o = 1.75

→ o = $0.35

Therefore one orange costs $0.35

Then one grapefruit costs g → ($1.95 - 3o)/2

                                               → g = ($1.95 - 3(0.35))/2

                                               → g = 0.45

Therefore one grapefruit costs $0.45

4 0
2 years ago
I need helppppp......
Roman55 [17]

Answer:

l and n are parallel

Step-by-step explanation:

360° around a point

65° x 2 = 130

360 - 130 = 230

230/2 = 115

115 ° are corresponding angles

3 0
3 years ago
What is the equation of the following line written in slope-intercept form?
adelina 88 [10]

Answer:

y = 5x

Step-by-step explanation:

The y intercept is 0 since it crosses the y axis at 0

The slope is rise over run

From (0,0) we go up 5 and to the right 1

5/1 = 5

Slope = 5

The slope intercept equation is

y = mx+b where m is the slope and b is the y intercept

y = 5x+0

y = 5x

4 0
3 years ago
Read 2 more answers
Please help me i don't know what to do <br> please show your work
Diano4ka-milaya [45]
<h3>Distributive Property</h3>

The distributive property lets you group or ungroup terms using parentheses. It lets you multiply an external factor by every term in parentheses, expressing the result as a sum:

... a(b + c) = ab + ac . . . . . . factor <em>a</em> multiplies the terms <em>b</em> and <em>c</em>

and it lets you remove a common factor from different terms, putting that factor outside parentheses:

... ab + ac = a(b + c)

The letters <em>a</em>, <em>b</em>, <em>c</em> here can stand for any number or expression.

<h3>Homework</h3>

20. To do this problem, you need to eliminate the parentheses using the distributive property. Then, "collect terms," which is another application of the distributive property. The external factor outside the parentheses is (-2/3). Multiply that by each term in parentheses, and add the results.

After that, recognize that c is a factor of two of the terms. Add their coefficients to simplify that sum to one term.

-\dfrac{2}{3}(12c-9)+14c=\left(-\dfrac{2}{3}\right)(12c)+\left(-\dfrac{2}{3}\right)(-9)+14c=-8c+6+14c\\\\=c(-8+14)+6\\\\=6c+6

22. You are to evaluate the expression with x=2 two ways: as is, and after you simplify it by combining like terms.

<u>As is:</u>

-8x+5-2x-4+5x\\=-8(2)+5-2(2)-4+5(2)\\=-16+5-4-4+10\\=-9

<u>Simplified:</u>

-8x+5-2x-4+5x\\=x(-8-2+5)+(5-4)=-5x+1\\=-5(2)+1=-10+1\\=-9

I prefer simplifying the expression first. The number of calculations and chances for error are reduced.

23. It is convenient to check for equivalence after simplifying both expressions.

<u>First Expression:</u>

8x^2+3\left(x^2+y\right)=8x^2+3x^2+3y=11x^2+3y

<u>Second Expression:</u>

7x^2+7y +4x^2-4y=(7+4)x^2+(7-4)y=11x^2+3y

The simplified forms of the expressions are identical, so we conclude the expressions are equivalent.

25. The area of a rectangle is the product of its length and width. Here, you are asked to simplify the product of (3+x) ft and 3 ft.

((3+x)\,\text{ft})(3\,\text{ft})=(3\,\text{ft})\cdot (3\,\text{ft})+(x\,\text{ft})\cdot (3\,\text{ft})=9\,\text{ft}^2+3x\,\text{ft}^2\\\\=(3x+9)\,\text{ft}^2

In the last form of this expression, we have used "standard form" which has the degree of the variable decreasing in terms left to right. The units are factored out to make the expression a bit less cumbersome.

3 0
3 years ago
Read 2 more answers
ASAP! GIVING BRAINLIEST! Please read the question THEN answer correctly! No guessing. Show your work or give an explaination.
aksik [14]

Answer:

6-2y

Step-by-step explanation:

when transposed

3x+6y=18 becomes

3x=18-6y

x=18-6y/3

x=6-2y

hope this helps

plz mark me brainliest

8 0
3 years ago
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