Answer:
The probability is 0.2326 or 23.26%.
Step-by-step explanation:
The probability that a random customer fills their tank with premium gas is:
[tex]P( prem\ \&\ fill) = 0.2*0.5=0.10[/tex]
The probability that a random customer fills their tank is given by:
[tex]P(fill)=P( reg\ \&\ fill)+P( mid\ \&\ fill)+P( prem\ \&\ fill)\\P(fill) = 0.5*0.3+0.3*0.6+0.2*0.5\\P(fill) = 0.43[/tex]
Therefore, the probability that a customer used premium gas given that hey have filled their tank is:
[tex]P(prem| fill) = \frac{P( prem\ \&\ fill) }{P(fill)} \\P(prem| fill) =\frac{0.10}{0.43}=0.2326[/tex]
The probability is 0.2326 or 23.26%.
Are You Ready for More?: Two raised to the 12th power is equal to 4,096. How many other
whole numbers can you raise to a power and get 4,096? Explain or show your reasoning.
(1 Point)
2^12 = 4096
Answer:
4, 8, 16,64 and 4096.
Step-by-step explanation:
We are already given: [tex]4096=2^{12}[/tex]
To determine other whole numbers that can be raised to a power to obtain 4096, we apply the product rule of indices.
Product Rule of Indices: [tex]a^{xy}=(a^x)^y[/tex]
Now 12 can be factored in the following ways where one of the terms must be a perfect square:
12=2 X 612 =6 X 212 =3 X 412 =4 X 312=1 X 12[tex]2^{12}=(2^2)^6=4^6\\\\2^{12}=(2^6)^2=64^2\\\\2^{12}=(2^4)^3=16^3\\\\2^{12}=(2^3)^4=(8^2)^2=8^{2*2}=8^4\\\\2^{12}=(2^{12})^1=4096^1 $(This is the trivial case)[/tex]
Therefore, the other whole numbers that can be raised tp a power to obtain 4096 are: 4, 8, 16, 64 and 4096.
Determine the magnitude of the resultant force by adding the rectangular components of the three forces.
a) R = 29.7 N
b) R = 54.2 N
c) R = 90.8 N
d) R = 24.0 N
Assuming that $3u + 12v\neq0$, simplify $\dfrac{12u^3 + 48u^2v}{3u+12v}$.
Answer:
4u²
Step-by-step explanation:
[tex]\dfrac{12u^3 + 48u^2v}{3u+12v}=\dfrac{12u^2(u+4v)}{3(u+4v)}=\boxed{4u^2}[/tex]
Common factors cancel from numerator and denominator. The one factor that might make the expression undefined is given as non-zero, so no additional restrictions apply.
Company A makes a large shipment to Company B. Company B can reject the shipment if they can conclude that the proportion of defective items in the shipment is larger than 0.1. In a sample of 400 items from the shipment, Company B finds that 59 are defective. Conduct the appropriate hypothesis test for Company B using a 0.05 level of significance.
Answer:
[tex]z=\frac{0.1475-0.1}{\sqrt{\frac{0.1(1-0.1)}{400}}}=3.17[/tex]
The p value for this case would be given by:
[tex]p_v =P(z>3.17)=0.00076[/tex]
For this case the p value is lower than the significance level so then we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 0.1 and then Company B can reject the shipment
Step-by-step explanation:
Information provided
n=400 represent the random sample taken
X=59 represent number of defectives from the company B
[tex]\hat p=\frac{59}{400}=0.1475[/tex] estimated proportion of defectives from the company B
[tex]p_o=0.1[/tex] is the value to verify
[tex]\alpha=0.05[/tex] represent the significance level
z would represent the statistic
[tex]p_v[/tex] represent the p value
Hypothesis to test
We want to verify if the true proportion of defectives is higher than 0.1 then the system of hypothesis are.:
Null hypothesis:[tex]p \leq 0.1[/tex]
Alternative hypothesis:[tex]p > 0.1[/tex]
The statistic would be given by:
[tex]z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}[/tex] (1)
Replacing the info given we got:
[tex]z=\frac{0.1475-0.1}{\sqrt{\frac{0.1(1-0.1)}{400}}}=3.17[/tex]
The p value for this case would be given by:
[tex]p_v =P(z>3.17)=0.00076[/tex]
For this case the p value is lower than the significance level so then we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 0.1 and then Company B can reject the shipment
The sum of one and the product of 4 and a number x
Answer:
1 + 4x
Step-by-step explanation:
Let's break this down.
"The sum of one" means that something is being added to the number one:
1 +
"and" whatever comes after the word 'and' will be added to the number one
"the product of 4 and a number x" this means that the number four and the variable x are being multiplied:
4x
Put it together:
1 + 4x
Therefore, the expression is 1 + 4x.
For the given equation, find the values of a, b, and c, determine the direction in which the parabola opens, and determine the y-intercept. Decide which table best illustrates these values for the equation: y = x squared minus 6 x Table A a b c up or down y-intercept 1 -6 0 up (0,0) Table B a b c up or down y-intercept 1 0 0 up (0,-6) Table C a b c up or down y-intercept 1 6 0 up (0,0) Table D a b c up or down y-intercept 1 -6 0 down (0,0) a. Table A c. Table C b. Table B d. Table D Please select the best answer from the choices provided
Answer:
The table that illustrates this equation is table A:
1 -6 0 up (0,0)
Step-by-step explanation:
The values of the parameters a, b, and c have to agree with the values for the general quadratic equation in standard form:
[tex]y = a\,x^2+b\,x+c[/tex]
compared to:
[tex]y=x^2-6\,x[/tex]
So the coefficient "a" of the quadratic term in our case is: "1"
the coefficient "b" of the linear term is : "-6"
the coefficient "c" for the constant term s : "0" (zero)
since the coefficient "a" is a positive number, we know that the parabola's branches must be opening "UP".
The y intercept can be found by evaluating the expression for x = 0:
[tex]y=x^2-6x\\y=(0)^2-6\,(0)\\y=0[/tex]
Therefore the y-intercept is at (0, 0)
These results agree with those of Table "A"
Answer:
Table A.)
Step-by-step explanation:
a 1, b -6, c 0, up, (0, 0), Table A.
Which statements are true?
If all angles of a quadrilateral are right angles, then the quadrilateral must be a square.
Two shapes are similar if and only if their corresponding angles are equal.
All quadrilaterals have four sides, and the sum of all angles in a quadrilateral is 180º.
if the diagonals of a quadrilateral are perpendicular bisectors, then the quadrilateral must be a rhombus.
There are three vertices in a triangle, or there are four sides in a pentagon.
Any two triangles are either similar or congruent.
Answer:
Step-by-step explanation:
1) If all angles of a quadrilateral are right angles, then the quadrilateral must be a square. This is not true because the quadrilateral can also be a rectangle.
2) Two shapes are similar if and only if their corresponding angles are equal. This is true.
3) All quadrilaterals have four sides, and the sum of all angles in a quadrilateral is 180º. This is false because the sum of the angles is 360°
4) if the diagonals of a quadrilateral are perpendicular bisectors, then the quadrilateral must be a rhombus. This is true.
5) There are three vertices in a triangle, or there are four sides in a pentagon. This is false because a Pentagon has 5 sides.
6) Any two triangles are either similar or congruent. This is not true. Congruent triangles are always similar
Therefore, the true statements are 2 and 4
Answer:
its B and D
Step-by-step explanation:
A fluctuating electric current II may be considered a uniformly distributed random variable over the interval (9, 11)(9,11). If this current flows through a 2-ohm resistor, find the probability density function of the power P = 2I^2P=2I 2 .
Answer:
Step-by-step explanation:
A fluctuating electric current II may be considered a uniformly distributed random variable over the interval (9, 11)
[tex]p_1=\{^{\frac{1}{2}:9\leq i\leq 11}_{0:otherwise[/tex]
Now define
[tex]p = 2I^2[/tex]
[tex]\Rightarrow I^2=(\frac{p}{2} )\\\\\Rightarrow I=(\frac{p}{2} )^{\frac{1}{2} }\\\\\Rightarrow h^{-1}(p)=(\frac{p}{2} )^{\frac{1}{2}}[/tex]
[tex]\frac{dh^{-1}}{dp} =\frac{d[h^{-1}(p)]}{dp} \\\\=\frac{d(p/2)^{\frac{1}{2} }}{dp}[/tex]
[tex]=\frac{1}{2} \times \frac{1}{2} (\frac{p}{2} )^{{\frac{1}{2}-1} }\\\\=\frac{1}{4}(\frac{p}{2} )^{{\frac{1}{2}-1} }\\\\=\frac{1}{2}(\frac{2}{p} )^{{\frac{1}{2}} }[/tex]
using the transformation method, we get
[tex]f_p(p)=f_1(h^{-1}(p))|\frac{d[h^{-1}(p)]}{dp} |\\\\=\frac{1}{2} \times \frac{1}{4} (\frac{2}{p} )^{\frac{1}{2} }\\\\=\frac{1}{8} (\frac{2}{p} )^{\frac{1}{2} }[/tex]
[tex]f_p(p)=\{^{\frac{1}{8} (\frac{2}{p} )^{\frac{1}{2} },162\leqp\leq 242} }_{0,otherwise}[/tex]
Find the circumference of each circle, use 3.14 for . Include units and round to the nearest tenth. Show work
7. The circumference of a circle is 34.54 cm. What is the diameter and radius of the circle? (Show work)
8. What is the circumference of a circle in terms of , if it has a radius of 3.5 in?
(in terms of means do not substitute 3.14 for pi, leave the symbol in the final answer)
Answer:
Answer:-
a) The circumference of the circle C = 21.98 m
b) The circumference of the circle C = 37.68 ft
c) The circumference of the circle C = 40.82 km
d) The radius of the circle = r = 11 c.m
The Diameter of the circle 'd' = 2(r) = 2(11) =22 c.m
e) The circumference of the circle = 21.98 inches
Step-by-step explanation:
a) In First diagram
Given radius of the circle 'r' = 7.1 m
The circumference of the circle C = 2πr
C = 2 (3.14) (7.1)
C = 21.98 m
The circumference of the circle C = 21.98 m
b) In second diagram
Given diameter of the circle 'd' = 12 ft
The circumference of the circle C = 2πr
C = π(2 r)
Diameter = 2 X radius
d = 2 r
The circumference of the circle C = πd
C = 3.14 ×12
The circumference of the circle C = 37.68 ft
c)
Given diameter of the circle 'd' = 13 km
The circumference of the circle C = 2πr
C = π(2 r)
Diameter = 2 X radius
d = 2 r
The circumference of the circle C = πd
C = 3.14 ×13
The circumference of the circle C = 40.82 km
7) The circumference of the circle C = 2πr
Given The circumference of a circle is 34.54 cm
Now 2πr = 34.54
2(3.14) r = 34.54
[tex]r = \frac{34.54}{3.14} = 11[/tex]
The radius of the circle = r = 11 c.m
The Diameter of the circle 'd' = 2(r) = 2(11) =22 c.m
8) Given radius of the circle 'r' = 3.5 inches
The circumference of the circle C = 2πr
C = 2 (3.14) (3.5)
C = 21.98
The circumference of the circle = 21.98 inches
1. The mean of the data set{9,5,y,2,x} is twice the data set {8,x,4,1,3}. What is (y-x) squared.
2. How many alcohol must be added to480 grams of hand sanitizer that is 24% alcohol to make it a hand sanitizer that is 40% alcohol?
Answer:
1. (y - x)² = 256
2. 128g needed to be added
Step-by-step explanation:
1.
9 + 5 + 2 + y + x = 2(8 + 4 + 1 + 3 + x)
16 + y + x = 32 + 2x
y - x = 16
∴ (y - x)² = 256
2.
x = mass of alcohol to add
480 × 0.24 = 115.2 ← current mass of alcohol
0.4(480 + x) = 115.2 + x (×5)
2(480 + x) = 576 + 5x
960 + 2x = 576 + 5x
3x = 384
x = 128g
Statistics show that about 42% of Americans voted in the previous national election. If three Americans are randomly selected, what is the probability that none of them voted in the last election
Answer:
19.51% probability that none of them voted in the last election
Step-by-step explanation:
For each American, there are only two possible outcomes. Either they voted in the previous national election, or they did not. The probability of an American voting in the previous election is independent of other Americans. So we use the binomial probability distribution to solve this question.
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.
42% of Americans voted in the previous national election.
This means that [tex]p = 0.42[/tex]
Three Americans are randomly selected
This means that [tex]n = 3[/tex]
What is the probability that none of them voted in the last election
This is P(X = 0).
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 0) = C_{3,0}.(0.42)^{0}.(0.58)^{3} = 0.1951[/tex]
19.51% probability that none of them voted in the last election
What is the y-intercept of a line that has a slope of -3 and passes through point (0, -7)?
Answer:
Step-by-step explanation:
line equation: y=mx + C
substitute given values
-7 = -3*0 + C
C=y= -7 ANS
A marine biologist is preparing a deep-sea submersible for a dive. The sub stores breathing air under high pressure in a spherical air tank that measures wide. The biologist estimates she will need of air for the dive. Calculate the pressure to which this volume of air must be compressed in order to fit into the air tank. Write your answer in atmospheres. Round your answer to significant digits.
The complete question is;
A marine biologist is preparing a deep-sea submersible for a dive. The sub stores breathing air under high pressure in a spherical air tank that measures 78.0 cm wide. The biologist estimates she will need 2600 L of air for the dive. Calculate the pressure to which this volume of air must be compressed in order to fit in to the air tank. Write you answer in atmospheres
Answer:
10.5 atm
Step-by-step explanation:
Formula for Volume of a sphere is;
V = (4/3)πr³
r = 78/2 = 39 cm
V = (4/3)π(39)³
V = (4/3)*π*59319
V = 248475 cm³
Now, from conversions, 1000 cm³ = 1L
So,
V = 248475/1000
V = 248.5 L
This is the volume of the storage tank
If we assume that the 2600 L of air is measured at 1 atmosphere pressure, then we will obtain the following relationship:
From Boyles law,
P1 × V1 = P2 × V2
Thus;
(1 atm) × (2600 L) = (P2) × (248.5 L)
P2 = 2600/248.5
P2 = 10.463 atmospheres
Approximating to 3 significant figures is; P2 = 10.5 atm
What is the image of R for a dilation with center (0,0) and a scale factor of 1 1/2?
Answer: The image is (6,-3)
Step-by-step explanation:
The coordinates of R is ( 4,-2) and to find the image using the scale factor 1.5 you will multiply the x coordinates by 1.5 and the y coordinate also by 1.5 to have the new image of R.
4 * 1.5 = 6
-2 * 1.5 = -3
The new coordinates care (6, -3)
You are writing music for a movie and you have to synchronize the music to the amount of frames per click in it. It's a battle scene so you want fast, energetic and exciting music. You choose a Presto tempo marking of 200 beats per minute. How many picture frames are there per each tempo click? (Round to the nearest whole number and write only the number.)
Answer: 7.2 frames per bit.
Step-by-step explanation:
Our teempo is 200 bpm.
in one minute we have 60 seconds, so here we have:
200b/60s = 3.33 bits per second.
For movies, the standar is 24 frames per second
now, we can take the quotient between the frames per second and the bits per second and get the frames per bit.
24fps/3.33bps = 7.2 frames per bit.
Please answer this correctly
Answer:
698 cm²
Step-by-step explanation:
The volume is given by ...
V = LWH
Filling in the given values, we have ...
1020 = (17)(5)y . . . . . . . using L=17, W=5, H=y
y = 1020/(17·5) = 12
The surface area is given by ...
A = 2(LW +H(L+W))
A = 2(17·5 +12(17+5)) = 2(85 +264) . . . . . . . using L=17, W=5, H=y=12
A = 698 . . . . square centimeters
A farmer knows that every 50 eggs his chickens lay, only 45 will be marketable. If his
chickens lay 1000 eggs in a week, how many of them will be marketable?
Answer:
900 eggs
Step-by-step explanation:
45/50 are marketable
divide the top and bottom by 5
9/10
Multiply this fraction by the 1000 eggs laid
9/10 *1000
900 eggs will be marketable
Answer:
900
Step-by-step explanation:
a triangle has an area of 15 cm. a similar triangle is drawn using a scale factor of 3.5. what is the area of the similar triangle to the nearest square cm?
Answer:
184 square cm
Step-by-step explanation:
The ratio of areas is the square of the ratio of the scale factor. The larger triangle has an area of ...
(15 cm²)(3.5²) = 183.75 cm²
The area of the similar triangle is about 184 cm².
Which numbers are solutions of the inequality below? (Select all that apply.)
x − 2 < −8
a) 6
b) −6
c) 4
d) −8
Answer:
d) −8
Step-by-step explanation:
x − 2+2 < −8+2
x < -6
The only number less than -6 is -8
The length and with of a rectangle are consecutive odd integers . The perimeter is 104 meters .find the length and with
Answer:
25 m, 27 m
Step-by-step explanation:
The perimeter is twice the sum of length and width, so that sum is 52 m. Half that is the average of length and width, so will be the even integer between the two consecutive odd integers.
52/2 = 26
The length and width are 25 m and 27 m.
Mai deposited $4000 into an account with 4.8% interest, compounded quarterly. Assuming that no withdrawals are made, how much will she have in the
account after 7 years?
Do not round any intermediate computations, and round your answer to the nearest cent.
Answer:
5,586.17
Step-by-step explanation:
A = $ 5,586.17
A = P + I where
P (principal) = $ 4,000.00
I (interest) = $ 1,586.17
Compound Interest Equation
A = P(1 + r/n)^nt
Where:
A = Accrued Amount (principal + interest)
P = Principal Amount
I = Interest Amount
R = Annual Nominal Interest Rate in percent
r = Annual Nominal Interest Rate as a decimal
r = R/100
t = Time Involved in years, 0.5 years is calculated as 6 months, etc.
n = number of compounding periods per unit t; at the END of each period
A humanities professor assigns letter grades on a test according to the following scheme. A: Top 12% of scores B: Scores below the top 12% and above the bottom 61% C: Scores below the top 39% and above the bottom 21% D: Scores below the top 79% and above the bottom 6% F: Bottom 6% of scores Scores on the test are normally distributed with a mean of 67.7 and a standard deviation of 7.8. Find the minimum score required for an A grade. Round your answer to the nearest whole number, if necessary.
Answer:
The minimum score required for an A grade is 77.
Step-by-step explanation:
When the distribution is normal, we use the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.
In this question, we have that:
[tex]\mu = 67.7, \sigma = 7.8[/tex]
Find the minimum score required for an A grade.
Top 12% of scores get an A.
100-12 = 88th percentile.
The 88th percentile of scores is the minimum required for an A grade. This score is X when Z has a pvalue of 0.88. So X when Z = 1.175.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]1.175 = \frac{X - 67.7}{7.8}[/tex]
[tex]X - 67.7 = 7.8*1.175[/tex]
[tex]X = 76.865[/tex]
Rounding to the nearest whole number:
The minimum score required for an A grade is 77.
Write the standard form of the line that passes through the given points. Inclide your work in the final answer. Type your answer in the box provided or use the upload option to submit your solution. (4,7) and (0,7)
Answer:
y=7
Step-by-step explanation:
Slope: 7-7/4-0=0
Point: (0,7)
pt/slope form:
y-7=(0)(x-0)
y=7
Need help ASAP please!!
Answer:
AOB = 73
BOC = 107
Step-by-step explanation:
So make an equation.
9x + 27 = 180
9x = 153
x = 17
AOB = 73
BOC = 107
Help asap giving branlist!!!
Answer:
B
Step-by-step explanation:
Let's arrange it into slope-intercept form.
2x - y = 4
y = 2x - 4
We are looking for a line with slope of 2 and y-intercept -4. This line is Line B.
the average mark of candidates in an aptitude test was 138.5 with a standard deviation of 10.6. three scores extracted from the test are 178,122,100.what is the average of the extracted scores that are extreme value
Answer:
The average of the extracted scores = 133.33
Step-by-step explanation:
Given data the average mark of candidates in an aptitude test was 138.5 with a standard deviation of 10.6
mean of the aptitude test = 138.5
Standard deviation of the aptitude test = 10.6
Given three scores extracted from the test are 178,122,100
The average of the extracted scores = ∑x / n
The average of the extracted scores
= [tex]\frac{178 +122 +100}{3}[/tex]
= 133.33
Final answer:-
The average of the extracted scores = 133.33
Is f(x) continuous at x equals 4? Why or why not? A. No, f(x) is not continuous at x equals 4 because ModifyingBelow lim With x right arrow 4 f (x )does not exist. B. Yes, f(x) is continuous at x equals 4 because f (4 )exists. C. No, f(x) is not continuous at x equals 4 because f (4 )is undefined. D. Yes, f(x) is continuous at x equals 4 because ModifyingBelow lim With x right arrow 4 f (x )equals f (4 ).
Corrected Question
Is the function given by:
[tex]f(x)=\left\{\begin{array}{ccc}\frac{1}{4}x+1 &x\leq 4\\4x-11&x>4\end{array}\right[/tex]
continuous at x=4? Why or why not? Choose the correct answer below.
Answer:
(D) Yes, f(x) is continuous at x = 4 because [tex]Lim_{x \to 4}f(x)=f(4)[/tex]
Step-by-step explanation:
Given the function:
[tex]f(x)=\left\{\begin{array}{ccc}\frac{1}{4}x+1 &x\leq 4\\4x-11&x>4\end{array}\right[/tex]
A function to be continuous at some value c in its domain if the following condition holds:
f(c) exists and is defined.[tex]Lim_{x \to c}$ f(x)[/tex] exists. [tex]f(c)=Lim_{x \to c}$ f(x)[/tex]At x=4
[tex]f(4)=\dfrac{1}{4}*4+1=2[/tex][tex]Lim_{x \to 4}f(x)=2[/tex]Therefore: [tex]Lim_{x \to 4}f(x)=f(4)=2[/tex]
By the above, the function satisfies the condition for continuity.
The correct option is D.
if a-2= (2^2/3+2^1/3) find a^3-6a^2+12a-14
Answer:
Step-by-step explanation:
7. 1, for r = 0 - 1, for r = 1 Hence, determine alo. Using characteristic root ... find the solution of the recurrence relation y, + 9 y, 2 = 6y, 1, subjected to the ... Solve a, -5a, 1 + 6a, 2 = 0 , given initial conditions ao = 2 and a1 = 5. ... Solve the recurrence relation a, – 7a, 1 + 16a, 2 – 12a, 3 = 0 for n > 3 with ... 2"; 3. a = (2)” – n.
Answer:
2
Step-by-step explanation:
I solved in the picture
Hope this helps ^-^
1. O perímetro de um quadrado é 20 cm. Determine sua diagonal. 1 ponto a) 2 √5 cm b) 20√2 cm c) 5√2 cm d) 2√10 cm
Answer:
c) 5√2 cm
Step-by-step explanation:
A square with side length l has a perimeter given by the following equation:
P = 4l.
In this question:
P = 20
So the side length is:
4l = 20
l = 20/4
l = 5
Diagonal
The diagonal forms a right triangle with two sides, in which the diagonal is the hypothenuse. Applying the pytagoras theorem.
[tex]d^{2} = l^{2} + l^{2}[/tex]
[tex]d^{2} = 5^{2} + 5^{2}[/tex]
[tex]d^{2} = 50[/tex]
[tex]d = \pm \sqrt{50}[/tex]
Lenght is a positive meausre, so
[tex]d = \sqrt{50}[/tex]
[tex]d = \sqrt{2 \times 25}[/tex]
[tex]d = \sqrt{2} \times \sqrt{25}[/tex]
[tex]d = 5\sqrt{2}[/tex]
So the correct answer is:
c) 5√2 cm
4. Dean Pelton wants to perform calculations to impress the accreditation consultants, but upon asking for information about GPAs at Greendale Community College, Chang only tells Pelton that the GPAs are distributed with a probability density function f(x) = D(2 + e −x ), 2 ≤ x ≤ 4 where D was some unknown "Duncan" constant. How many student records have to be retrieved so that the probability that the average GPA is less than 2.3 is less than 4 percent?
Answer:
the minimum records to be retrieved by using Chebysher - one sided inequality is 17.
Step-by-step explanation:
Let assume that n should represent the number of the students
SO, [tex]\bar x[/tex] can now be the sample mean of number of students in GPA's
To obtain n such that [tex]P( \bar x \leq 2.3 ) \leq .04[/tex]
⇒ [tex]P( \bar x \geq 2.3 ) \geq .96[/tex]
However ;
[tex]E(x) = \int\limits^4_2 Dx (2+e^{-x} ) 4x = D \\ \\ = D(e^{-x} (e^xx^2 - x-1 ) ) ^D_2 = 12.314 D[/tex]
[tex]E(x^2) = D\int\limits^4_2 (2+e^{-x})dx \\ \\ = \dfrac{D}{3}[e^{-4} (2e^x x^3 -3x^2 -6x -6)]^4__2}}= 38.21 \ D[/tex]
Similarly;
[tex]D\int\limits^4_2(2+ e^{-x}) dx = 1[/tex]
⇒ [tex]D*(2x-e^{-x} ) |^4_2 = 1[/tex]
⇒ [tex]D*4.117 = 1[/tex]
⇒ [tex]D= \dfrac{1}{4.117}[/tex]
[tex]\mu = E(x) = 2.991013 ; \\ \\ E(x^2) = 9.28103[/tex]
∴ [tex]Var (x) = E(x^2) - E^2(x) \\ \\ = .3348711[/tex]
Now; [tex]P(\bar \geq 2.3) = P( \bar x - 2.991013 \geq 2.3 - 2.991013) \\ \\ = P( \omega \geq .691013) \ \ \ \ \ \ \ \ \ \ (x = E(\bar x ) - \mu)[/tex]
Using Chebysher one sided inequality ; we have:
[tex]P(\omega \geq -.691013) \geq \dfrac{(.691013)^2}{Var ( \omega) +(.691013)^2}[/tex]
So; [tex](\omega = \bar x - \mu)[/tex]
⇒ [tex]E(\omega ) = 0 \\ \\ Var (\omega ) = \dfrac{Var (x_i)}{n}[/tex]
∴ [tex]P(\omega \geq .691013) \geq \dfrac{(.691013)^2}{\frac{.3348711}{n}+(691013)^2}[/tex]
To determine n; such that ;
[tex]\dfrac{(.691013)^2}{\frac{.3348711}{n}+(691013)^2} \geq 0.96 \\ \\ \\ (.691013)^2(1-.96) \geq \dfrac{-3348711*.96}{n}[/tex]
⇒ [tex]n \geq \dfrac{.3348711*.96}{.04*(.691013)^2}[/tex]
[tex]n \geq 16.83125[/tex]
Thus; we can conclude that; the minimum records to be retrieved by using Chebysher - one sided inequality is 17.
