Complete question is;
Researchers from the Educational Testing Service (ETS) found that providing immediate feedback to students answering openended questions can dramatically improve students’ future performance on exams (Educational and Psychological Measurement, Feb. 2010). The ETS researchers used questions from the Graduate Record Examination (GRE) in the experiment. After obtaining feedback, students could revise their answers. Consider one of these questions. Initially, 50% of the students answered the question correctly. After providing immediate feedback to students who answered incorrectly, 70% answered correctly. Consider a bank of 100 open-ended questions similar to those on the GRE. a. In a random sample of 20 students, what is the probability that more than half initially answer the question correctly? b. Refer to part a . After providing immediate feedback, what is the probability that more than half of the students answer the question correctly?
Answer:
A) 41.2%
B) 95.2%
Step-by-step explanation:
This is a binomial probability distribution problem, so we will use the formula;
P(k) = (n!/(k!(n - k)!) × p^(k) × (1 - p)^(n-k)
A) Initially, 50% of the students answered the question correctly.
Thus, p = 0.5
Also,n = 20
Now, the probability that more than half initially answer the question correctly would be:
P(k > 10)
This can be expressed as;
P(k > 10) = P(11) + P(12) + P(13) + P(14) + P(15) + P(16) + P(17) + P(18) + P(19) + P(20)
P(11) = (20!/(11!(20 - 11)!) × 0.5^(11) × (1 - 0.5)^(20-11) = 0.1602
Similarly,
P(12) = (20!/(12!(20 - 12)!) × 0.5^(12) × (1 - 0.5)^(20-12) = 0.1201
P(13) = (20!/(13!(20 - 13)!) × 0.5^(13) × (1 - 0.5)^(20-13) = 0.0739
Using online binomial probability calculator we can get the remaining values which are;
P(14) = 0.037
P(15) = 0.0148
P(16) = 0.0046
P(17) = 0.0011
P(18) = 0.0002
P(19) = 0.00002
P(20) = 0
Thus;
P(k > 10) = 0.1602 + 0.1201 + 0.0739 + 0.037 + 0.0148 + 0.0046 + 0.0011 + 0.0002 + 0.00002 + 0 ≈ 0.41192 = 41.2%
B) After providing immediate feedback, we are told that 70% answered correctly.
Thus; p = 70% = 0.7
Similar to A above and using online binomial probability calculator, we have;
P(11) = 0.0654
P(12) = 0.1144
P(13) = 0.1643
P(14) = 0.1916
P(15) = 0.1789
P(16) = 0.1304
P(17) = 0.0716
P(18) = 0.0278
P(19) = 0.0068
P(20) = 0.0008
Thus;
P(k > 10) = 0.0654 + 0.1144 + 0.1643 + 0.1916 + 0.1789 + 0.1304 + 0.0716 + 0.0278 + 0.0068 + 0.0008 = 0.952 = 95.2%
It is found that on average, 9% of the population recycles its garbage. Under this assumption, if a random sample of 120 households in Iowa City is taken, would you be surprised to find that fewer than 3% of households in the sample recycle their garbage? Use the fact that p-hat has an approximately normal distribution. Group of answer choices I would not be surprised because there are lots of lazy students in Iowa City. I would not be surprised because 3% is not that far away from 9%. I would be surprised because Iowa City is a very clean community which means lots of people recycle their garbage. I would be surprised because if the 9% average is true, the chance of a sample proportion being less than 3% is very small (only 1%). Who cares? It's only garbage!
Complete Question
It is found that on average, 9% of the population recycles its garbage. Under this assumption, if a random sample of 120 households in Iowa City is taken, would you be surprised to find that fewer than 3% of households in the sample recycle their garbage? Use the fact that p-hat has an approximately normal distribution.
Group of answer choices
A I would not be surprised because there are lots of lazy students in Iowa City.
B I would not be surprised because 3% is not that far away from 9%.
C I would be surprised because Iowa City is a very clean community which means lots of people recycle their garbage.
D I would be surprised because if the 9% average is true, the chance of a sample proportion being less than 3% is very small (only 1%). Who cares? It's only garbage!
Answer:
The correct option is D
Step-by-step explanation:
From the question we are told that
The sample size is n = 120
The mean of the proportion is p = 0.09
Generally the standard deviation is mathematically represented as
[tex]\sigma = \sqrt{\frac{p(1-p)}{n} }[/tex]
=> [tex]\sigma = \sqrt{\frac{0.09(1-0.09)}{120 } }[/tex]
=> [tex]\sigma = 0.02612[/tex]
Generally the chance that fewer than 3% of households in the sample recycle their garbage is mathematically represented as
[tex]P(X < 0.03) = P( \frac{X - p}{\sigma} < \frac{0.03 -0.09}{0.02612} )[/tex]
[tex]P(X < 0.03) = P( Z < -2.297 )[/tex]
From the z-table
[tex]P( Z < -2.297 ) = 0.01[/tex]
=> [tex]P(X < 0.03) = 0.01/tex]
=> [tex]P(X < 0.03) = 1\% /tex]
Label each triangle
Answer: Top right and left are ACUTE, Bottom right is RIGHT, and bottom left is OBTUSE.
Answer:
the top two are acute triangles
the third(bottom left is an obtuse angle
and the last one(bottom right) is a right triangle
Step-by-step explanation:
the top angles are all under 90 degrees which is what makes them acute
the bottom left triangle has an angle greater than 90 which makes it obtuse
and the bottom right has a right angle, which makes it a right triangle
Describe what happens if you divide a difference by 3.
question is attached thanks
Take two points
(0,0)(-2,-4)Slope:-
[tex]\\ \sf\longmapsto \dfrac{-4}{-2}=2[/tex]
Equation in point slope form
[tex]\\ \sf\longmapsto y-y_1=m(x-x_1)[/tex]
[tex]\\ \sf\longmapsto y=2x[/tex]
In slope intercept form
y=2x+0Answer:
Step-by-step explanation:
Line passes through origin (0, 0) so y-intercept is zero: b=0
At x=2, y=4 so slope is 4/2=2: m=2
Answer is y = 2x
GUYS HELP ME WITH THIS WILL MARK BRANLIEST
Create a system of linear equations with no solution. In your final answer, include the system of equations and the graphs of the lines.
Answer:
A border of 3 cm width is printed on 500 sheets of paper, each of length 40 cm and width 30 cm fit costs 50p to print 100 cm of border, find the total cost of printing the border.
Rashad has 24 almonds and 32 walnuts for making snack bags. He wants to make as many snack bags as possible and wants each bag to have the same amount of almonds and walnuts. What is the largest number of snack bags he could make?
Question 4 options:
3 bags
4 bags
8 bags
16 bags
Answer:
4 bags
Step-by-step explanation:
Answer:
3 bags
Step-by-step explanation:
each bag will have 8 almonds and 8 walnuts.
Angles a and B are supplementary if the measure of the angle a is 81 what is the measure of angle b
Answer: 99
Step-by-step explanation:
Supplementary angles add to 180 degrees, 180-81=99
Bob the builder is making 540 kg of concrete mix.
Concrete is made by mixing cement, sand and gravel in the ratio 1:3:5
How much gravel does he need?
Answer:
300 kg
Step-by-step explanation:
Let Constant Ratio be x:
x+3x+5x = 540
9x = 540
x = 60 kg
So, weight of gravel (W) = 5x
5 x 60
W = 300 kg (ANS)
I chose the first one please help if its not correct. Simplify.
y+ (15+ y)
15 + 2 y
17 y
15 y
15+ y
Answer:
15+2y
Step-by-step explanation:
take y to the other side
Carmen bought a desktop computer and a laptop computer. Before finance charges, the laptop cost $200 less than the desktop. She pald for the computers
using two different financing plans. For the desktop the interest rate was 9% per year, and for the laptop it was 7% per year. The total finance charges for one
year were $306. How much did each computer cost before finance charges?
Which sequence of steps is a correct derivation of the difference quotient for f(x) = ln(4 – x) – 1?
Answer:
Step-by-step explanation:
3.
Billy has 20 pencils. Melissa gives Billy some shells.
Billy has 20 pencils. Now Billy has 36 shells. How many shells did Melissa
give him?
melissa give him?
Answer:
36. Melissa did not give Billy any pencils.
Answer:
Step-by-step explanation:
Melissa gave Billy 36 shells
1 Josiah is making a candle by pouring melted wax into a mold in the shape of a square pyramid. Each side of the base of the pyramid is 12 in and the height of the pyramid is 14in. To get the wax for the candle, Josiah melts cubes of wax that are each 6 in by 6 in by 6 in. How many of the wax cubes will Josiah need in order to make the candle? Show your work.
Answer:
3.11 wax cubes
Step-by-step explanation:
plz help idk what to do :(
Answer:
x=5°
∠JIK=110°
Step-by-step explanation: From question,
20x-10+8x-20=140-6x
28x-30=140-6x
34x=170
x=170/34
x=5°
Eq. in ∠JIK,
140-30
=110°
Please answer right ....
Answer:
[tex]2\frac{13}{120}[/tex]
Step-by-step explanation:
**Fractions for addition and/or subtraction need equal denominators
Alike denominators in parentheses
[tex]4\frac{2}{5} -(1\frac{2}{3}+\frac{5}{8})\\4\frac{2}{5} -(1\frac{2}{3}(\frac{8}{8}) +\frac{5}{8}(\frac{3}{3} ))\\4\frac{2}{5}-(1\frac{16}{24}+\frac{15}{24})\\4\frac{3}{5} -(1\frac{31}{24} )\\4\frac{3}{5} -(2\frac{7}{24} )[/tex]
[tex]4\frac{2}{5}-2\frac{7}{24}[/tex]
Solve
[tex]4\frac{2}{5}-2\frac{7}{24} \\4\frac{2}{5}(\frac{24}{24}) -2\frac{7}{24}(\frac{5}{5})\\4\frac{48}{120}-2\frac{35}{120}\\2\frac{13}{120}[/tex]
solution for .05n + .10d = .75
Answer:
d=−0.5n+7.5, n=−2d+15
Step-by-step explanation:
Which statement is true about the prime polynomial 2x2 + 3x + 3?
It cannot be modeled with a rectangle.
It can be modeled with a square.
It cannot be modeled with all positive tiles.
It can only be modeled with an odd number of tiles.
Answer:
A
Step-by-step explanation:
because problem make more sences
Answer:
A it cannot be modeled with a rectangle
Step-by-step explanation:
Please help me with this
Answer:
Step-by-step explanation:
Both angles added together = 180 degrees. They both have a straight line as their base.
So let <ABC = x
Then <CBD = 3x Add the two angles
x + 3x = 180 Combine
4x = 180 Divide by 4
4x/4 = 180/4
x = 45
So 3x = 3*45 = 135
5055 X 550 + 32 - 99 + 43333 X 5 =
first right gits branlist
Answer:
the answer is 2996848
Step-by-step explanation:
Dudley Durite deposited $350 into a savings account that earns 6.5% interest compounded semi annually. What amount was in his account at the end of 1 year?
Answer:
$373.12
Step-by-step explanation:
You want to set this up with the equation for compound interest which is [tex]A=P(1+\frac{r}{n})}^{nt}[/tex]. A stands for amount, P stands for principle which in this case is 350, r is rate which for this one is .065, ad n is the amount of times compounded per year, and since it is compounded semi annually you do 2 for 2 times a year. Your equation based on this information should look like this:
[tex]A=350(1+\frac{.065}{2})}^{(2)(1)}[/tex]
After working this out you get A = 373.12
$373.12
Where do humans and other animals get their food?
Answer:
Humans and other animals get their food from plants directly or indirectly. Humans and animals are heterotrophic organisms, so they obtain their food from other organisms.
Step-by-step explanation:
∧
Answer:
From plants and other animals
Step-by-step explanation:
Got it right on my quiz haha..
Lizzie runs every 8 days and Wilson runs every 12 days. If they both ran together today, in how many days will they run together again?
Answer:
We have to find the LCM(least common multiple) of the two numbers.
24 is the LCM, because;
Multiples of 8 are -
8 x 1 = 8
8 x 2 = 16
8 x 3 = 24
Multiples of 12 are -
1 x 12 = 12
2 x 12 = 24
24 is their least common multiple.
Which of the following r-values represents the strongest correlation?
Which of the following r-values represents the strongest correlation?
A. -0.51 B.-0.71 C. -0.41 D. -0.61
Answer:
-0.71
Step-by-step explanation:
Generally, a value of r greater than 0.7 is considered a strong correlation. Anything between 0.5 and 0.7 is a moderate correlation, and anything less than 0.4 is considered a weak or no correlation.
The r-value that represents the strongest correlation is -0.71.
What is correlation?Any of the many metrics used to describe the strength and direction of a linear relationship between two random variables is called a correlation coefficient.
So, r stands for the correlation coefficient.
Depending on the direction of the association, an r-value may be either negative or positive.
Yet, the link is greater the closer an r-value is to 1.
Here - 0.71 is closer to -1 then it is having a strongest correlation.
Learn more about correlation coefficient here:
brainly.com/question/27226153
#SPJ7
Please help!! I'm pretty sure it's A or D. I'm not sure which one though.
look at this equation and the steps used to solve it. Which answer is the best justification for step 1 of this solution
Answer:
equal quantities something...
Step-by-step explanation:
Points A, B, and C are on line AC.
A horizontal line has points A, B, C. A line extends from point B up and to the left to point D. Angle D B C is 140 degrees.
Angle CBD has a measure of 140°. What is the measure of angle ABD?
40°
50°
60°
70°
Answer:
50° Because considering the total angles is still half a line segment 50° is
Answer:
40 degrees A for me on EDG 2022
Step-by-step explanation:
June 21st
What number times 10 equals 30 tens
Answer:
30
Step-by-step explanation:
Because 30 tens = 300
30 x 10 = 300
a person buys a washing machine in the condition that he shall pay sum of INR 5880 at the cash down payment and the same sum at the end of the first year and two years. what is the total interest paid by him in this scheme, if the rate of interest is 5% compounded yearly?
Answer: $827
Step-by-step explanation:
Given that :
Cash down payment = 5880
Payment at end of first year = 5880
Payment at end of second year = 5880
Interest rate = 5% = 0.05 compounded yearly
Let purchase amount = y
Amount left after cash down = amount on which interest is paid = y - 5880
Interest at end of first year :
(y - 5880) * 0.05 = 0.05y - 294
Amount to pay plus interest :
Amount left after cash down payment - amount paid at end of first year + interest
y - 5880 - 5880 + 0.05y - 294
y - 12054 + 0.05y
= 1.05y - 12054
2nd year interest :
(1.05y - 12054) * 0.05
= 0.0525y - 602.7
Amount left + interest = 2nd year payment
(1.05y - 12054) + (0.0525y - 602.7) = 5880
1.1025y - 12656.7 = 5880
1.1025y = 5880 + 12656.7
1.1025y = 18536.7
y = 18536.7 / 1.1025
y = 16813.33
Hence,
Sales price of washing machine = 16813.33
Total amount paid = (5880 + 5880 + 5880) = 17640
Interest paid = $(17640 - 16813.33) = $826.67
= $827
The total interest paid by him in this scheme, if the rate of interest is 5% compounded yearly is INR 826.67
Given:
Down payment = INR 5880
Payment at end of first year = INR 5880 (same as down payment)
Payment at end of second year = INR 5880 (same as down payment)
Interest rate = 5%
= 5/100
= 0.05 compounded yearly
Amount of purchase = x
Amount remaining after down payment
= x - 5880
Interest at end of first year :
(x - 5880) * 0.05(5,880)
= 0.05x - 294
Amount to pay plus interest = Amount remaining after down payment - amount paid at end of first year + interest
= x - 5880 - 5880 + 0.05x - 294
= x - 12,054 + 0.05x
= 1.05x - 12,054
2nd year interest :
(1.05x - 12054) * 0.05
= 0.0525x - 602.7
Amount left + interest = 2nd year payment
(1.05x - 12054) + (0.0525x - 602.7) = 5880
1.1025x - 12656.7 = 5880
1.1025x = 5880 + 12656.7
1.1025x = 18536.7
divide both sides by 1.1025
x = 18536.7 / 1.1025
x = 16,813.33
Therefore, The cost of washing machine b is INR 16,813.33
Total amount paid = (5880 + 5880 + 5880) = INR 17,640
Amount of Interest paid = (17640 - 16813.33)
= INR 826.67
Read More:
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What is the Square root of 3664?
Answer:
60.5
Thanks!
Mark me brainliest!
~[tex]FieryAnswererGT[/tex]~
2(3x-4)=3x+1
I just need help solving this-
Answer:
x=3
Step-by-step explanation:
simplify
6x−8=3x+1
subtract 3x
3x−8=1
add 8 to each side
3x=9
divide both sides by 3
x=3