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lorasvet [3.4K]

3 years ago

6

the average score for a biology test is 77 and the standard deviation is 8. which percent best represents the probability that a

ny student scored between 61 and 93 on the test?

1 answer:

Olenka [21]3 years ago

5 0

Answer:

Lowkey, I am not very sure about this but it is most likely B

You might be interested in

Consider the equation below. f(x) = 2x3 + 3x2 − 336x (a) Find the interval on which f is increasing. (Enter your answer in inter

Vaselesa [24]

We have been given a function $f(x)=2x^3+3x^2-336x$ . We are asked to find the interval on which function is increasing and decreasing.

(a). First of all, we will find the critical points of function by equating derivative with 0.

$f'(x)=2(3)x^{2}+3(2)x^1-336$

$f'(x)=6x^{2}+6x-336$

$6x^{2}+6x-336=0$

$x^{2}+x-56=0$

$x^{2}+8x-7x-56=0$

$(x+8)-7(x+8)=0$

$(x+8)(x-7)=0$

$x=-8,x=7$

So $x=-8,7$ are critical points and these will divide our function in 3 intervals $(-\infty,-8)U(-8,7)U(7,\infty)$ .

Now we will find derivative over each interval as:

$f'(x)=(x+8)(x-7)$

$f'(-9)=(-9+8)(-9-7)=(-1)(-16)=16$

Since $f'(9)>0$ , therefore, function is increasing on interval $(-\infty,-8)$ .

$f'(x)=(x+8)(x-7)$

$f'(1)=(1+8)(1-7)=(9)(-6)=-54$

Since $f'(1)$ , therefore, function is decreasing on interval $(-8,7)$ .

Let us check for the derivative at $x=8$ .

$f'(x)=(x+8)(x-7)$

$f'(8)=(8+8)(8-7)=(16)(1)=16$

Since $f'(8)>0$ , therefore, function is increasing on interval $(7,\infty)$ .

(b) Since $x=-8,7$ are critical points, so these will be either a maximum or minimum.

Let us find values of f(x) on these two points.

$f(-8)=2(-8)^3+3(-8)^2-336(-8)$

$f(-8)=1856$

$f(7)=2(7)^3+3(7)^2-336(7)$

$f(7)=-1519$

Therefore, $(-8,1856)$ is a local maximum and $(7,-1519)$ is a local minimum.

(c) To find inflection points, we need to check where 2nd derivative is equal to 0.

Let us find 2nd derivative.

$f''(x)=6(2)x^{1}+6$

$f''(x)=12x+6$

$12x+6=0$

$12x=-6$

$\frac{12x}{12}=-\frac{6}{12}$

$x=-\frac{1}{2}$

Therefore, $x=-\frac{1}{2}$ is an inflection point of given function.

3 0

3 years ago

A supplier delivers an order for 20 electric toothbrushes to a store. By accident, three of the electric toothbrushes are defect

Vladimir79 [104]

The probability that the first two electric toothbrushes sold are defective is 0.016.

The probability of an event, say E occurring is:

$P(E)=\frac{n(E)}{N}$

Here,

n (E) = favorable outcomes

N = total number of outcomes

Let X = the number of defective electric toothbrushes sold.

The number of electric toothbrushes that were delivered to a store is n = 20.

The number of defective electric toothbrushes is x = 3.

The number of ways to select two toothbrushes to sell from the 20 toothbrushes is:

$(\left {{20} \atop {2}} \right. )$ $=\frac{20!}{2!(20-2)!} =\frac{20!}{2!18!} =\frac{20*19*18!}{2!*18!} = 190$

The number of ways to select two defective toothbrushes to sell from the 3 defective toothbrushes is:

$(\left {{3} \atop {2}} \right. )$ $=\frac{3!}{2!(3-2)!} =\frac{3!}{2!1!} =\frac{3*2!}{1!2!} =3$

Compute the probability that the first two electric toothbrushes sold are defective as follows:

P (Selling 2 defective toothbrushes) = Favorable outcomes ÷ Total no. of outcomes

$\frac{3}{190}\\ =0.01579\\=0.016$

Thus, the probability that the first two electric toothbrushes sold are defective is 0.016.

Learn more about probability here brainly.com/question/27474070

#SPJ4

4 0

2 years ago

susan surveys 20 people in her math class to find out the most popular movie. 5 students say star wars if the are 200 students i

Eva8 [605]

5 out of 20 like Star Wars so what value (x) should like Star Wars out of 200. Set up a proportion comparing the two.

x= # of people in 7th gr who like Star Wars

5/20= x/200
cross multiply

(5*200)= (20*x)
1000= 20x
divide both sides by 20

50= x

ANSWER: 50 people in the 7th grade should like Star Wars.

Hope this helps! :)

8 0

4 years ago

Read 2 more answers

Hello everyone! if anyone knows how to do trigonometry please answer my question (with as much detail as you can) as im a little

Gemiola [76]

Answer:

AB = 5cm

AC = 12cm

BC = 13cm

A = 90 deg

B= arctan(AC/AB)=arctan(12/5) =67.38 deg

C=arctan(AB/AC) =arctan(5/12) = 22.62 deg

7 0

3 years ago

the bookstore normally sells mechanical pencils for ¢6.50 .this week the pencils are discounted by 25‰ to the nearest cent, what

dezoksy [38]

The discount takes off 1.63

5 0

3 years ago