In a 20 item true-false examination, if 12 correct answers constitute a passing grade,
what is the probability that someone will pass, if they are guessing?
A. .8398
B. .2517
C. .1201
D. .1317
Answer:
The answer is B, I know this because I just took a test with this question lol
If 12 correct answers constitute a passing grade on a 20-item true-false exam, the probability that someone will pass is 1/2 if they are guessing.
What is meant by probability?Probability is synonymous with possibility. It is a mathematical branch that deals with the occurrence of a random event. The value ranges from zero to one. Probability has been introduced in mathematics to predict the likelihood of events occurring. Probability = the number of possible paths to success. The total number of possibilities For example, the probability of flipping a coin and getting heads is 12, because there is only one way to get a head and there are two possible outcomes.Therefore,
Let X denote the number of correctly answered questions out of a total of 20.
Bernoulli trails are formed by repeated coin tosses. Because the "head" on a coin represents the correct answer and the "tail" represents the incorrect answer, the questions that are correctly answered are Bernoulli trials.
[tex]$&\therefore \mathrm{p}=\frac{1}{2} \\[/tex]
[tex]&\therefore \mathrm{q}=1-\mathrm{p}=1-\frac{1}{2}=\frac{1}{2}[/tex]
X follows a binomial distribution with n = 20 and p = 1/2
[tex]&\therefore P(X=x)={ }^n C_x q^{n-x} p^x \\[/tex]
[tex]&={ }^{20} C_x\left(\frac{1}{2}\right)^{20-x} \cdot\left(\frac{1}{2}\right)^x \\[/tex]
[tex]&={ }^{20} C_x\left(\frac{1}{2}\right)^{20}[/tex]
P ( at least 12 questions answered correctly )= P (X ≥ 12)
[tex]&=\mathrm{P}(\mathrm{X}=12)+\mathrm{P}[/tex][tex](\mathrm{X}=13)+\ldots+\mathrm{P}(\mathrm{X}=20) \\[/tex]
[tex]&={ }^{20} \mathrm{C}_{12}\left(\frac{1}{2}\right)^{20}+{ }^{20}[/tex][tex]\mathrm{C}_{13}\left(\frac{1}{2}\right)^{20}+\ldots+{ }^{20}[/tex][tex]\mathrm{C}_{20}\left(\frac{1}{2}\right)^{20} \\[/tex]
[tex]&=\left(\frac{1}{2}\right)^{20} \cdot\left[{ }^{20} \mathrm{C}_{12}+{ }^{20} \mathrm{C}_{13}+\ldots+{ }^{20} \mathrm{C}_{20}\right][/tex]
Hence, If 12 correct answers constitute a passing grade on a 20-item true-false exam, the probability that someone will pass is 1/2 if they are guessing.
The complete question is:
In an examination, 20 questions of true-false type are asked. Suppose a student tosses a fair coin to determine his answer to each question. If the coin falls heads, he answers 'true', if it falls tails, he answers 'false'. Find the probability that he answers at least 12 questions correctly.
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An environmental engineer is tasked with determining whether a power plant cooling system is heating the water it uses more than allowed by environmental regulations. They measure water temperatures at the cooling system input and the cooling system output for several different days in several different seasons.A data file containing these measurements is HW_PTA 243.csv.Do a statistical analysis on this data to determine if the temperature change between the input and output of the cooling system is different than 6 degrees. What does your analysis indicate?
A) The cooling system changes the temperature of the water by an amount different than 6 degrees.
B) The cooling system changes the temperature of the water by 6 degrees.
Complete Question
The complete question is shown on the first , second and third uploaded image
Answer:
A
The correct option is A
B
The correct option is H
Step-by-step explanation:
The null hypothesis is [tex]H_o : \mu_1 - \mu_2 = 6[/tex]
The alternative hypothesis is [tex]H_a : \mu_1 - \mu_2 \ne 6[/tex]
The population mean difference is [tex]\mu_d = 6[/tex]
Generally the sample size is n = 15
Generally the sample mean for input temperature is mathematically represented as
[tex]\= x _1 = \frac{\sum x_i }{n}[/tex]
=> [tex]\= x _1 = \frac{57.6 + 68.9 + \cdots +60.4 }{15}[/tex]
=> [tex]\= x _1 = 62.57 [/tex]
Generally the sample mean for output temperature is mathematically represented as
[tex]\= x _2 = \frac{\sum x_i }{n}[/tex]
=> [tex]\= x _2 = \frac{65.1+ 74.4 + \cdots +67.3 }{15}[/tex]
=> [tex]\= x _2 = 55.97 [/tex]
Generally the sample mean difference is mathematically represented as
[tex]\= d = 62.57 - 55.97[/tex]
=>[tex]d = 6.6[/tex]
Generally the standard deviation is mathematically represented as
[tex]s_d = \sqrt{\frac{ \sum [d_1 - \= d]^2}{n-1} }[/tex]
=> [tex]s_d = \sqrt{\frac{ [ [57.6 -65.1]- 6.6]^2 +[68.9 -74.4]- 6.6]^2+\cdots + [60.4 -67.3]- 6.6]^2}{15-1} }[/tex]
=> [tex]s_d = 1.732 [/tex]
Generally the test statistics is mathematically represented as
[tex]t = \frac{6.6 - 6 }{\frac{1.732}{\sqrt{15} } }[/tex]
=> [tex]t = 1.342 [/tex]
Generally the degree of freedom is mathematically represented as
[tex]df = n - 1[/tex]
So
[tex]df = 15 - 2[/tex]
=> [tex]df = 14[/tex]
Generally the p-value is mathematically represented as
[tex]p-value = 2 * P(t > 1.342 )[/tex]
Generally from the t -distribution table the probability of 1.342 at a degree of freedom of [tex]df = 28[/tex] is
[tex]P(t > 1.342 ) = 0.10047[/tex]
So
[tex]p-value = 2 * 0.10047[/tex]
=> [tex]p-value = 0.201[/tex]
Generally from the value obtained we see that [tex]p-value > \alpha[/tex] Hence
The decision rule is
Fail to reject the null hypothesis
The conclusion is
The cooling system changes the temperature of the water by 6 degrees
1. We have 50 pounds of dog food to last for 10 days. Each day we use the same
amount of food. How much dog food is used each day?
Answer:
5 pounds
Step-by-step explanation:
50 pounds of dog food divided by 10 days = 5 pounds per day for 10 days.
Molly has 9 cups of flour. If this is 3/4 of the number she needs to make bread, how many cups does she need?
use a tape diagram by reading it backward, draw a tape diagram and label it unknown.
Answer:
She needs 12 cups of flour to make bread
Step-by-step explanation:
9 divided by 3 is 3. So you add 3 to 9 and you get 12. So yeah!
If 30% of the pupils in a school are boys, what percentage of the pupils are girls?
Answer:
70%
Step-by-step explanation:
Multiply. Write your answer as a fraction in simplest form.
3
6x
22
Please help and by the way the question is 6 x 3 over 22 (fraction)
Answer:
9/11
Step-by-step explanation:
(6 × 3)/22
18/22 = 9/11
A farmer decided to put a fence around his property that measures 170 feet long and 120 feet wide. What is the perimeter of his property?
Answer:
290 ft is the perimeter
Step-by-step explanation:
170+120=290 ft
580 feet.
To find perimeter, you have to add up all the sides, so add length, length, width, and width.
170+ 170+120+120
This gives you 580 ft.
Don't forget the unit!
If this helped, please mark branliest
The price of a DVD is $24.00 plus 8% sales tax. What is the sales tax on
this DVD in dollars and cents?
34 points
$3.00
$300
$1.92
$192
Answer:
1.92
Step-by-step explanation:
Answer:
$1.92
Step-by-step explanation:
8% of 24
= 1.92
Fifty students are going on a field trip. Twenty of the students are boys. What percent of the students are girls?
Answer:
60% would be the correct answer
Step-by-step explanation:
The girls percentage among students is 60%.
What is a percentage?A percentage is a proportion that shows a number as parts per hundred. If we have to calculate percent of a number, divide the number by the whole and multiply by 100.
For the given situation,
Total number of students = 50
Number of boys = 20
Number of girls = [tex]50-20[/tex]
⇒ [tex]30[/tex]
Thus, girls percentage is
⇒ [tex]\frac{30}{50}(100)[/tex]
⇒ [tex]60[/tex]
Hence we can conclude that the girls percentage among students is 60%.
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The equation of a circle is (x−2)2+(y+6)2=100. Find the equation of a circle that is externally tangent to the given circle and has a center at (18, −6).
Answer:
(x-18)^2+(y+6)^=36
Step-by-step explanation:
circle basic equation is (x-h)^2+(y-k)^2=r^2
center is (18,-6) it is also externally tangent
so
(x-18)^2+(y+6)^2=36 answer
The equation of a circle that is externally tangent to the given circle and has a center at (18, −6) is [tex](x-18)^2+(y+6)^=36[/tex]
What is an equation of a circle?A circle can be characterized by its center's location and its radius's length. Let the center of the considered circle be at (h,k) coordinate.
Let the radius of the circle be 'r' units.
Then, the equation of that circle would be:
[tex](x-h)^2 + (y-k)^2 = r^2[/tex]
Given that the circle basic equation is [tex](x-2)^2+(y+6)^2=100[/tex]
The center is (18,-6) it is also externally tangent;
Therefore,
[tex](x-18)^2+(y+6)^2=36[/tex]
Therefore, the equation of a circle that is externally tangent to the circle is; [tex](x-18)^2+(y+6)^2=36[/tex]
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AC Sports also manufactures tennis balls. It sells these in sets of three. The tennis
ball container is cylindrical with a radius of 3 inches and a height of 8.5 inches. The
marketing department is planning to create a new label to wrap around the container
and hopefully increase sales. Approximately how much space is there for a label that
wraps around the container?
Answer:
about 216.77 inches of space
Step-by-step explanation:
2πrh+2πr²
2π(3)(8.5)+2π(3)²
2π25.5+2π9
51π+18π
216.769893
about 216.77 inches of space
help im confused..........
Answer:
rvefncoqjefadsNofvewnvfeeljjnfvqe
Step-by-step explanation:
fdcopjsfddcaxjefwpojdsjandipewhhqdaspcixpjewfs;odkcnewoasjjncikkjasn;kcjnnsixjfiasxhcjnsdaxo[okckiefihihehabficphbkjckd khksdk a help me
Answer:
lol im confused aswell
Step-by-step explanation:
The graph below shows y is a function of x.
Answer: false
Step-by-step explanation:
Solve for x for the following pls!
1) 7+3x+1=4x+5
2) 8+2x+18=x+19
3) 6+2x+13=x+26
would appreciate it sm
Answer:
1.x=3
2. x= -7
3. x=7
Step-by-step explanation:
Profit is the amount of money that remains after all expenses of a project have been paid. Acme Construction has just completed the construction of a building, and Fred Jones, the project manager, is doing the final accounting. Acme bid $232,500 for the project and was awarded a contract for that amount. The cost of construction, including labor, building materials, and other expenses such as equipment rental was $198,468. What was the profit on this project?The total amount of profit is $______.
Answer:
$34032
Step-by-step explanation:
Acme bid $232,500 for the project and was awarded a contract for that amount.
The cost of construction, including labor, building materials, and other expenses such as equipment rental was $198,468.
We know that,
Profit = The amount of money that remains after all expenses of a project have been paid
Profit = $232,500-$198,468
= $34032
Hence, the profit is $34032.
Explain how sample size affects statistical significance.
Answer:
More formally, statistical power is the probability of finding a statistically significant result, given that there really is a difference (or effect) in the population. ... So, larger sample sizes give more reliable results with greater precision and power, but they also cost more time and money.
7
Felicia is making trail mix. The recipe calls for 3 cups pretzels and 1.5 cups of m&m's.
She wants to make 27 cups of trail mix for a birthday party. How many cups of pretzels and m&m's does she need?
Answer:
81 Cups of Pretzels and 40.5 Cups of M&M's
Step-by-step explanation:
p= Pretzels
m= M&M;s
3p+1.5m= 1
3(27)+ 1.5(27)
81 + 40.5
Samia buys 15 1/2 yards of fabric to make shirts for his friends he needs 2 5/6 yards of fabric to make each shirt how many shirts can Sammy make
Answer: He can make 5 shirts
Step-by-step explanation:
15 1/2 ÷ 2 5/6 = 5 8/17
two angles of a triangle measure 12° and 40° what id the measure of the third angle of the triangle
Answer:
128
Step-by-step explanation:
The sum of angles in the triangle is 180 degrees
12 + 40 + x = 180
52 + x = 180
x= 180 - 52 = 128 degrees
(x is the third angle of the triangle)
Credit: study1104 for the answer: they originally answered this question, though i copy and pasted to help you with your assignment! Hope this helps, wanted to include credit so your aware where the answer came from!!
The following table shows the height of a plant at different ages.
Age (in weeks)
3
7
10
Height (in centimeters)
12
35
60
Is the height of the plant proportional to its age?
Choose 1 answer:
А
Yes
B
No
Answer:
the answer to this question would be A
The temperature in Denver is -4 degrees
Celsius and the temperature if Tampa is 38
degrees Celsius. What is the difference
3) between these two temperatures?
Answer:
34 degrees Celsius
Step-by-step explanation:
For this question, you just find the sum of the two temperatures:
-4+38 = 34
How many times does three go into 35 m
Answer:
11 times
Step-by-step explanation:
35 divided by 3 = something like 11.6666666666. . .
That means that 3 only goes into 35 11 times since you don't count the 0.666666666. . .
Hope I helped :)
Please comsider Brainliest :)
[tex]\huge\boxed{11\;times.}[/tex]
We have the question...
How many times does 3 go into 35?
Well, this is pretty simple all you have to do is count up by 3s until you get to the number. Remember, it doesn't have to be exact though. So, here we go count by threes 11 times. We get 33 from 3*11. Therefore, your answer will be 11 times.
PLEASE ANSWER I HAVE 10 MINUTES!!!
Answer:
1,3,4
Step-by-step explanation: hope this helps you
If tan t=5/7, what is tan(t−Pi)?
Answer:
-0.04
Step-by-step explanation:
tan([tex]\frac{5}{7}[/tex] - π) = -0.04
Given:
[tex]\text{tan}(t)=\frac{5}{7}[/tex]
To find:
Value of [tex]\text{tan}(t-\pi )[/tex]
Solution:
To solve the given expression we will use the identity,
[tex]\text{tan}(A-B)=\frac{\text{tan}A-\text{tan}B}{1+\text{tan}A\text{tan}B}[/tex]
Now substitute the values,
[tex]A=t[/tex]
[tex]B=\pi[/tex]
[tex]\text{tan}(t-\pi)=\frac{\text{tan}t-\text{tan}\pi }{1+\text{tan}t\text{tan}\pi }[/tex]
Since, the value of [tex]\text{tan}(\pi )[/tex] is [tex]0[/tex].
[tex]\text{tan}(t-\pi)=\frac{\text{tan}t-0}{1+\text{tan}t\times (0)}[/tex]
[tex]=\frac{\text{tan}t}{1}[/tex]
[tex]=\text{tan}t[/tex]
Therefore, [tex]\text{tan}(t-\pi)=\frac{5}{7}[/tex] will be the answer.
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What is the slope of the line y-5=3(x-2)?
209.106 in expender form
Answer:
209.106 = (2 x 100) + (0 x 10) + (9 x 1) + (1/10) + (0/100) + (6/1000)
Answer:
200+9+0.1+0.006.
Step-by-step explanation:
Help the pic is right here
Answer:
i think its C
Step-by-step explanation:
Answer:
D
Step-by-step explanation:
its just division tbh
Plz help
What is |5 x -3|?
-15
⊝
-8
⊝
15
⊝
8
Answer:
What type of math is this
Step-by-step explanation:
i poopoo myself how to clean
Answer:
you clean!?
Step-by-step explanation:
I just lick it
Answer:
use toilet paper
Step-by-step explanation:
first you clean yourself then you clean again until very clean lol
Help!!! ASAP!!!
The sum of the areas of a polyhedron’s face is
A: Its perimeter divide by two.
B: its surface area.
C: its volume
D: non of these
Answer: The sum of the area of it's faces
Step-by-step explanation: its the surafce area.