Answer:
a) [tex]n = 20[/tex] and [tex]p = 0.25[/tex]
b) The mean number of correct guesses in 20 cards for subjects who are just guessing is 5.
c) 0.2023 = 20.23% probability of exactly 5 correct guesses in 20 cards if a subject is just guessing
Step-by-step explanation:
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
The expected value of the binomial distribution is:
[tex]E(X) = np[/tex]
The standard deviation of the binomial distribution is:
[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]
A. The count of correct guesses in 20 cards has a binomial distribution. What are n and p?
20 cards mean that [tex]n = 20[/tex]
A subject who is just guessing has a one in four chance of guessing correctly on each card, which means that [tex]p = \frac{1}{4} = 0.25[/tex]
B. What is the mean number of correct guesses in 20 cards for subjects who are just guessing?
Expected value, so
[tex]E(X) = np = 20*0.25 = 5[/tex]
The mean number of correct guesses in 20 cards for subjects who are just guessing is 5.
C. What is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?
This is P(X = 5). So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 5) = C_{20,5}.(0.25)^{5}.(0.75)^{15} = 0.2023[/tex]
0.2023 = 20.23% probability of exactly 5 correct guesses in 20 cards if a subject is just guessing
Equation in point slope form (5,-12);m=-2/3
Answer:
y + 12 = -2/3(x - 5)
Write 383 in expanded form
Answer:
300 + 80 + 3
PLease mArk me brainliest
Solve the equation x – 15 = 42.
x=
Answer:
x = 57
Step-by-step explanation:
42 + 15 = 57
Solve the system by substitution
2x + 10y = -32
x = -9y
0.7+x=12 i reallly need help soo badd plss
Answer:
x=11.3
Step-by-step explanation:
happy to help ya :)
Answer:
x=11.3
Step-by-step explanation:
We do -0.7 on both sides and 12-0.7 is 11.3. So, x=11.3
Why would someone choose to use a graphing calculator to solve a system of linear equations instead of graphing by hand? Explain your reasoning.
Step-by-step explanation:
a graphing calculator is more accurate then graphing by hand especially when you dont know the exactly were the point is
Answer:
a graphing calculator is just easier to graph the points than having to put every point on a piece of graph paper. the calculator also can tell you a bunch of other things like the domain or range or y intercept or x intercept. it’s just all along easier
Step-by-step explanation:
I have no clue if this is the sample response so watch out
Pls help me jenejfnnfnwndndbenjwjdndnwkjs
Answer:
I have no clue
Step-by-step explanation:
HAHA
Roger goes shopping and saves $48 with a 30% off coupon. What was his total bill before tax
Answer:
160$
Step-by-step explanation:
160*.30=48
paige was planning to watch marathon episodes of her favorite show. the show had 48 episodes with each episode lasting exactly 22 minutes. if she planned to spend 4 days watching the show how many minutes should she watch each day?
Answer: 12
Step-by-step explanation: I did the math
i need help asap due tonight
Answer:
3 bucks
Step-by-step explanation:
Answer:
d=3
Step-by-step explanation:
if the whole thing equals 19, and you know that part of it is 10, that leaves the rest of it to be 9. the rest is divided into 3s, if you know the whole section is 9 then all you would have to do is divide 9 by 3 and that would get you 3
'Nine less than the product of four and a number
Answer:
(4 x X)-9
Step-by-step explanation:
I think this is correct pls tell me if this is wrong
Hope this helps
The algebraic expression of Nine less than the product of four and a number is 4x-9.
What is Expression?An expression is combination of variables, numbers and operators.
The given sentence is 'Nine less than the product of four and a number.
We need to write this sentence as an algebraic expression.
We know that less than means there we used subtraction.
Product in the sentence means multiplication.
Let us consider x as the unknown number in the given expression.
the product of four and a number means four is multiplied with x. which is 4x.
Nine less than the product of four and a number
4x-9
Hence, the algebraic expression of Nine less than the product of four and a number is 4x-9.
To learn more on Expressions click:
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If the Volume of a rectangular prism is 720 what is the width
Height 8 cm
Length 10cm
width???
Answer:
The width of the rectangular prism is 9 cm.
Step-by-step explanation:
From the formula of the volume of a bar [tex]V=whl[/tex] we see that [tex]w=\frac{V}{hl}=\frac{720}{8\cdot 10} = 9[/tex] cm.
What is the measure of the obtuse angle in this figure?
Its not 180
Answer:
C
Step-by-step explanation:
7x+5=180
7x= 175
x- 25
so 5(25)+4= 129
which is C
if my answer helps please mark as brainliest.
Anyone know this answer
Which is a unit rate?
•68 students to 2 teachers
•80 feet in 20 seconds
•16 people 5 cars
•2 pounds per 1 month.
Answer:
Remember a unit rate is a rate where the the value in the denominator (or second value in a x to y rate) is 1.
Step-by-step explanation:
PLS HELP I’LL MARK BRAINLIEST!!! ALSO THE ANSWER IS NOT 118!
Answer:
B. 128
Step-by-step explanation:
so the sum of the interior angle is 180
180 - 76 is 104
since both sides are the same divide 104 with 2 to get 52
to find x = 180 - 52 = 128
How many tons are equal to 48,000 pounds?
4 tons
24 tons
240 tons
2,400 tons
Answer:
24 tons
Step-by-step explanation:
Have a great day!!
The Answer is 24
Hope this helps<3
Which equation in point-slope form describes the line that passes through the point (4,-5) and is perpendicular to
the line represented by - 7x + 2y = 14?
Answer:
y = -2/7x - 27/7
Step-by-step explanation:
first find the slope of the line -7x + 2y = 14 by solving for 'y'
2y = 7x + 14
y = 7/2x + 7
since the slope is 7/2 then the line that is perpendicular will need the opposite and reciprocal of 7/2 which is -2/7
knowing the slope ('m') and having the point (4, -5) we can find the y-intercept of the new line ('b')
y = mx + b
-5 = (-2/7)(4) + b
-5 = -8/7 + b
[change -5 into -35/7]
-35/7 + 8/7 = b
b = -27/7
put 'm' and 'b' into y = mx + b
y = -2/7x - 27/7
The NEC permits 20% of the cross sectional area in a wireway to be occupied by conductors.for an 8"×8"×6' long wireway the conductors can occupy. In squared?
Answer:
Step-by-step explanation:
Sjaoa
The required cross-sectional area in a wireway is 12.8 In squared.
What is the percentage?The percentage is defined as a ratio expressed as a fraction of 100.
What are Arithmetic operations?Arithmetic operations can also be specified by subtracting, dividing, and multiplying built-in functions.
+ Addition operation: Adds values on either side of the operator.
For example 4 + 2 = 6
- Subtraction operation: Subtracts the right-hand operand from the left-hand operand.
for example 4 -2 = 2
We have been given an 8"×8"×6' long wireway the conductors can occupy.
Since the NEC permits 20% of the cross-sectional area in a wireway to be occupied by conductors
So the required cross-sectional area in a wireway is
⇒ 20 % of ( 8"×8" )
⇒ 0.20 × (64 )
⇒ 12.8 In squared
Thus, the required cross-sectional area in a wireway is 12.8 In squared.
Learn more about the percentages here:
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Juanita borrowed $600 to purchase a new computer. She
was charged 7% interest for two years. She used the
simple interest formula to find the interest.
|=600(7)(2)
What error did Juanita make and how will her error affect
the interest she calculates? Explain.
Answer:
Forgot to turn the 7% into a 0.7... if you dont do that, then it will come out larger then it was supposed to be :)
Answer:
Sample response: Juanita did not change the 7% to the decimal 0.07. When she completes the problem as written, the interest will be greater than the money she borrowed.
Step-by-step explanation:
This is a sample response, be sure to change the wording up a bit.
Suppose that 3\%3%3, percent of over 200{,}000200,000200, comma, 000 books borrowed from a library in a year are downloaded. The librarians plan to take an SRS of 757575 books from the population of borrowed books to see what proportion of books sampled are downloaded. What are the mean and standard deviation of the sampling distribution of the proportion of downloaded books
Answer:
The mean of the sampling distribution of the proportion of downloaded books is 0.03 and the standard deviation is 0.0197.
Step-by-step explanation:
Central Limit Theorem
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
3% of books borrowed from a library in a year are downloaded.
This means that [tex]p = 0.03[/tex]
SRS of 75 books.
This means that [tex]n = 75[/tex]
What are the mean and standard deviation of the sampling distribution of the proportion of downloaded books
By the Central Limit Theorem
Mean: [tex]\mu = p = 0.03[/tex]
Standard deviation: [tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.03*0.97}{75}} = 0.0197[/tex]
The mean of the sampling distribution of the proportion of downloaded books is 0.03 and the standard deviation is 0.0197.
At a fair cake-eating contest, Bobby ate three cakes in 20 minutes. At the same speed, how long did it take to win the contest by eating twenty-one cakes? Give your answer in minutes
Answer:
140 minutes
Step-by-step explanation:
First divide 21 by 3 to get 7
Then do 20*7 to get 140 :)
Please Help! Will mark Brainliest!!
Answer:
x = π/4, 5π/4
Step-by-step explanation:
sin(x) - 2 = cos(x) - 2
sin(x) = cos(x)
x = π/4, 5π/4
help please !! ASAP
---------------------------------
Use the ratio table to solve the percent problem.
What percent is 6 out of 30?
2%
6%
20%
30%
Answer:
20%
Step-by-step explanation:
6x5=30
20x5=100
Answer:
30 is the correct answer
K+22=17 would be K=15 right plz correct me if I'm wrong
Answer:
k = -5
Step-by-step explanation:
a - (9b - 13b) =
a = 12, b = -2
I'm- sorry
Answer:
4
Step-by-step explanation:
A triangle with the angle
72°, 48°and 60°
Determine if the following statement are possible or impossible
Gabriela has dinner at a café and the cost of her meal is $45.00. Because of the service, she wants to leave a 15% tip. What is the total cost of her meal?
Answer:
the answer is 51.75
Step-by-step explanation:
609.0÷14
what is the anawer
Answer:
43.50 or 43.5
Step-by-step explanation:
A regular price of a bathing suit is $89.99. What is the new price of the bathing suit when it is 70% off the regular price?
Answer:
$26.99
Step-by-step explanation:
i multiplied $89.99×.7 to get $62.993 and subtracted that from the regular amount.
hope this is right and helps :)
Answer:
Step-by-step explanation:
89.99(1-70/100)
89.99(30/100)
$26.997
$27 (rounded to nearest cent)