Answer:
a) The mean is 18 and the standard deviation is 1.79.
b) The interpretation is that the standard deviation of the sample means of groups of 20 students will be of 1.79, which is the sample error, which is different from the population standard deviation.
c) 0.2005 = 20.05% probability that a sample of 20 students has a mean score of 19.5 or more.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
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.
Central Limit Theorem
The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
Mean of 18 and a standard deviation of 8.
This means that [tex]\mu = 18, \sigma = 8[/tex]
Sample of 20:
This means that [tex]n = 20, s = \frac{8}{\sqrt{20}} = 1.79[/tex]
(a) Calculate the mean and standard deviation of the sampling distribution of x¯.
By the Central Limit Theorem, the mean is 18 and the standard deviation is 1.79.
(b) Interpret the standard deviation from part (a).
The interpretation is that the standard deviation of the sample means of groups of 20 students will be of 1.79, which is the sample error, which is different from the population standard deviation.
(c) Find the probability that a sample of 20 students has a mean score of 19.5 or more.
This is 1 subtracted by the pvalue of Z when X = 19.5. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{19.5 - 18}{1.79}[/tex]
[tex]Z = 0.84[/tex]
[tex]Z = 0.84[/tex] has a pvalue of 0.7995
1 - 0.7995 = 0.2005
0.2005 = 20.05% probability that a sample of 20 students has a mean score of 19.5 or more.
hellp me for a brainly
Answer:
25π or 78.5mm²
Step-by-step explanation:
[tex]A=3.14*5^{2} \\ =3.14*25\\ =78.5[/tex]
Answer:
78.5 mm² or answer D.Step-by-step explanation:
The formula for the area of a circle is
A = π*r²
Now we can rewrite with the radius. *Note* I am using 3.14 for pi to make it easier*
A = π*5²
Solve
5² = 25
25 * 3.14 = 78.5
Now since the measurements were done in millimeters, we will add mm to the end.
Also since it is area, we need to add ²
78.5 mm²
Help help help help help help
Answer:
18.457
Step-by-step explanation:
Which expressions are equivalent to 6 + 12x?
Answer:
Expressions A, C, D are equivalent
Step-by-step explanation:
Equivalent expressions:
Two expressions are equivalent if they give the same result. So
Option A:
3(2 + 4x) =3*2 + 3*4x = 6 + 12x
So equivalent
Option B:
3(2 + 6x) + 2x = 3*2 + 3*6x + 2x = 6 + 18x + 2x = 6x + 20. So not equivalent
Option C:
5(1+2x) + 1 + 2x = 5*1 + 5*2x + 1 + 2x = 5 + 10x + 1 + 2x = 6 + 12x.
Equal, so equivalent
Option D:
7*(1+2x) - 2x - 1 = 7*1 + 7*2x - 2x - 1 = 7 + 14x - 2x - 1 = 6 + 12x
Equal, so equivalent.
Option E:
7*(1+2x) + 2x - 1 = 7*1 + 7*2x - 2x - 1 = 7 + 14x + 2x - 1 = 6 + 16x
Different, so not equivalent.
A culture of bacteria has an initial population of 35000 bacteria and doubles every 10 hours. Using the formula P_t = P_0\cdot 2^{\frac{t}{d}}P t =P 0 ⋅2 d t , where P_tP t is the population after t hours, P_0P 0 is the initial population, t is the time in hours and d is the doubling time, what is the population of bacteria in the culture after 3 hours, to the nearest whole number?
Answer:43090
Step-by-step explanation: Pt=35000*2 3/10
Pt= 43090.0545
literally a goat if someone gives me an answer for this please
Answer: D, 100
Step-by-step explanation:
Answer: 100 (D)
Step-by-step explanation:
cuz
Pleaseeeee help!!! I’ll give you best answer!!!!Solve each equation by completing the square.
2) x2 + 14x + 48 = 0
Answer:
x=-8
x=-6
Step-by-step explanation:
Don't really know how to explain this. I never was good at completing the squares.
Hope that this helps!
please answer
Step by step
Answer:
B) 20°
Step-by-step explanation:
The top half of the circle is equal to 180°...
13x + 3x + 2x = 180°
18x = 180°
x = 10°
Angle EOD is the opposite angle of 2x
2 (10) = 20°
Find the distance CD rounded
to the nearest tenth.
C = (-5,4) D = (5,8)
CD = [?]
HINT: Use the distance formula:
d = V(x2 - xı)2 + (y2 - yı)2
Answer:
The distance is of 10.8 units.
Step-by-step explanation:
Distance between two points:
Suppose that we have two points, [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex]. The distance between them is given by:
[tex]D = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
In this question:
C(-5,4) and D(5,8). So
[tex]D = \sqrt{(5-(-5))^2 + (8-4)^2} = \sqrt{10^2 + 4^2} = 10.8[/tex]
The distance is of 10.8 units.
The red figure is congruent to the blue figure. Which choice describes a sequence of transformations in which the blue figure is the image of the red figure? (In other words, try and map the red figure on the blue figure).
1. Rotate the triangle 90º counterclockwise about the origin and then translate it 10 units left and 9 units down.
2. Rotate the triangle 90º clockwise about the origin and then translate it 10 units left and 9 units down.
3. Rotate the triangle 90º counterclockwise about the origin then translate it 1 unit up.
4. Rotate the triangle 90º clockwise about the origin then translate it 1 unit up.
Answer:
2. Rotate the triangle 90º clockwise about the origin and then translate it 10 units left and 9 units down.Step-by-step explanation:
Easy way to take one of the vertices and apply the transformations1. Rotate the triangle 90º counterclockwise about the origin and then translate it 10 units left and 9 units down.
False2. Rotate the triangle 90º clockwise about the origin and then translate it 10 units left and 9 units down.
True(-3, 3) → (3, 3) → (3 - 10, 3 - 9) = (-7, -6)3. Rotate the triangle 90º counterclockwise about the origin then translate it 1 unit up.
False4. Rotate the triangle 90º clockwise about the origin then translate it 1 unit up.
FalseKevin takes classes at both Westside college and Pinewood college at Westside class fees are $98 per credit hour and Pinewood they are $115 per credit hour. Karen is taking combined total of 18 credit hours at the two schools. Suppose that she's taking W credit hours at Westside. Write an expression for the combined total dollar amount that she paid for the class fees
Answer:
y = 98(w) + 115(18 - w)
Step-by-step explanation:
The expression that represents how much Kevin spends for classes at both schools : (#credits at Westside)($98) + (#credits at pinewood)($115). If he takes all credits at Westside this is 18(98) + 0, which would be the lowest cost it could be, if he takes all credits at Pinewood this would be 0 + (18)(115) which would be the maximum Bob could pay for 18 credits. If y is the total cost of is courses, then y = 98(w) + 115(18 - w). Using the distributive property, this can be simplified.
If baseball were played on Mars, the balls would fly much farther than they
do on Earth. One could then speculate that the number of home runs hit
would be much greater on Mars. Mike expects that he would hit 50% more
home runs if he were playing baseball on Mars. If he hit 76 home runs on
Earth, how many home runs does he expect he would hit on Mars?
Answer: 114 homeruns on mars
Step-by-step explanation: 76 homeruns x 0.5 = 38
76+38 = 114
What is the length of the diagonal of a cube with a side length of 5 cm? Round to the nearest tenth.
O 7.1
O 8.7
O 21.3
O 26.7
Answer:
8.7
Step-by-step explanation:
formula
d = sqrt(s^2 + s^2 + s^2)
d = sqrt(3*5^2)
d = sqrt(75)
d = 8.7
Where did I get the formula? If the cube sits on one of its faces then the diagonal of that face is sqrt(s^2 + s^2) = sqrt(2s^2)
Now to get the third s^2, you have to realize the the diagonal you calculated in the previous remark is one of the legs for the cube's corner to corner diagonal. The other leg is the height squared which is also s^2.
Answer:
hello love! your answer is 8.7cm :)
Step-by-step explanation:
i got it right on edge !
What is the solution to the equation?
19 + 13x = 32
Record your answer in the boxes
below.
00000.00
+/-
I give brainleist
Answer:
the answer is x=1
Step-by-step explanation:
minus 19 on both sides
then divide by 13 on both sides
Will give brainless
This is due tomorrow at 12pm
Answer:
The most common rock-forming minerals are quartz, feldspar, mica, pyroxene, amphibole, and olivine. The most reliable way to identify a mineral is by using a combination of several tests. A crystal is a solid in which the atoms are arranged in repeating patterns.
Read each problem and decide what operation you
use to evaluate it. Then write the equation and solve
D1. The area of a rectangle is 14. sq cm
and one side is 4 cm. How long is the
other side?
Answer:
b = 3.5 cm
Step-by-step explanation:
Given that,
The area of a rectangle, A = 14. sq cm
The length of one side, l = 4 cm
We need to find the length of another side. The formula for the area of a rectangle is given by :
A = lb
So,
[tex]14=4b\\\\b=\dfrac{14}{4}\\\\b=3.5\ cm[/tex]
So, the length of the other side is equal to 3.5 cm.
Suppose you like to keep a jar of change on your desk. Currently, the jar contains the following: 17 Pennies 10 Dimes 19 Nickels 21 Quarters What is the probability that you reach into the jar and randomly grab a nickel and then, without replacement, another nickel? Express your answer as a fraction or a decimal number rounded to four decimal places.
Answer:
19/67
Step-by-step explanation:
I think this would be the answer. You add up 17,10,19, and 21, and then use the PROBABILITY of drawing the nickels which would be 19/67, im not sure tho, let me know if it works
The researchers chilled the beverages to 6°C. Participants drank the beverages at the same time each day for three days. During the 3 days of the experiment, the researchers feed each participant the same diet. On the third day participants spent 24 hours in a calorimeter chamber to measure their energy metabolism. The medical journal Obesity published the results in 2007. What is the purpose of double-blinding?
a. To control unintentional researcher bias in the execution of the experiment
b. To control for the participants' prior beliefs about energy drinks
c. To control both unintentional research bias and participant prior beliefs
Answer:
C. To control both unintentional research bias and participant prior beliefs
Step-by-step explanation:
Double blinding is a type of study where neither the participants nor the researchers know the treatment or intervention that the participants receive until the whole study/research is completed. This is very important because it means that the results gotten from the study have a very slim chance of being biased.
Thus,the correct answer is option C as it includes both the researcher and the participants
Which of the following is equivalent to the expression below?
4x + 2(3-x)
6x + 6
3x+6
5x + 6
2x +6
Answer:
2x + 6
Step-by-step explanation:
you have to factorize the above equation first and you'll get the answer
What is the approximate distance between Chaplain and Asherville?
OA. 30.9 miles
OB.
14.7 miles
O c.
29.8 miles
OD.
16.4 miles
Answer:
B
Step-by-step explanation:
Remark
I'm hesitant to get an exact answer. You could do that with the cos law for distance. To get an approximate answer you could use the Pythagorean Theorem.
I'll try the cos law first.
Formula
c^2 = a^2 + b^2 - 2abcos(C)
Givens
c = 24
a = 18
b = ?
Solution
24^2 = 18^2 + b^2 - 2*18*b*cos(94)
576 = 324 + b^2 - 36*b*(-0.0698)
0 = 324 - 576 + b^2 + 2.511b
0 = b^2 + 2.511 - 252
Using the quadratic formula, the roots are
b1 = 14.66
b2 = - 17.11
The second one has no meaning in the real world.
Answer
the distance is 14.66 miles from Chaplin to Asherville
Note: using the Pythagorean theorem gives 15.87 which I would count as a good approximation.
Answer:
14.7
Step-by-step explanation:
got 100% on plato
Original price of a computer: $2,600.00
Tax: 6%
What is the sales tax for this computer?
Answer:
156 is the tax
Step-by-step explanation:
2600 x .06 = 156
What is the measure of op С : 429 180°
Answer:
90
Step-by-step explanation:
the angles that are on the opposite side are same
LEARNED THIS IN FOURTH GRADE
I'm still in fourth grade
my math teacher taught us this separately.
I go to School for the Highly Gifted in Grand Prairie, Texas
9/11 = c/55
c=???
answwedbhksjbdew
\
Answer:
C=45
if 9/11 = c/55 you have to divide the c/55 by 9/11, resulting in c/9 = 5
multiply 9 by 5 to get 45
Step-by-step explanation:
Please help me simplify this!!! Thank you so much.
Answer:
[tex] {3}^{2} [/tex]
Step-by-step explanation:
♡ Good Lessons ♡
Answer:
it's indices tho so you'll use addition/subtraction rule
find the value of X in the triangle shown below
Answer:
62.
Step-by-step explanation:
The length 5.7 is the base since it is the side that isn't congruent to 1 mroe side. Therefore, the angles connected to it, including x, is congruent. Sum of angle in triangle=180. given angle 56. 180-56=124. x+x(congruent angles)=124. 2x=124. x=62.
Answer:
62
Step-by-step explanation:
180 - 56 = 124
124/2 = 62
plz help will give brainiest what is x if it equals y*z*f*r*356 if y=18 z=5 f=7 and r=28 quick help
Answer:
Step-by-step explanation:
NEED ANSWER ASAP WILL GIVE BRAINLIEST FOR CORRECT ANSWER
In a 30°-60°-90° triangle, the side opposite of the 60° angle is 5V3. What is the length of
the hypotenuse? Just write the number.
Answer:
10
Step-by-step explanation:
Can't do that. I have to write some sort of explanation or the mods have a fit.
Side opposite = 5 √3
Sin(60) = √3 /2
Hypotenuse = x
Sin(60) = √3/2 = 5√3 / x
√3/2 = 5√3 / x Multiply both sides by x
x √3/2 = 5√3 Divide both sides by √3
x/2 = 5
x = 10
The hypotenuse is 10 units long.
What is the perimeter of the shaded part of this??
Answer:
18.9cm ( I rounded of and used Π as 3.14)
Step-by-step explanation:
P=distance all round
=1\2ΠD +Πd
see you have to calculate the upper length of the circle , since its half u multiply by a half. And since its not fully shaded the two semi circles are now included as the lower part of the whole shape. so you add them too. (I hope I'm making sense)
Avery has 6 yards of ribbon. He needs 1/3 yard to make 1 bow.
How many bows can Avery make
Which ordered pair represents a solution? *
A (0,2)
B (1,3)
C (3,1)
D (26)