Using the z-distribution, we have that:
a) A sample of 601 is needed.
b) A sample of 93 is needed.
c) A. Yes, using the additional survey information from part (b) dramatically reduces the sample size.
In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]\alpha[/tex], we have the following confidence interval of proportions.
[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
In which z is the z-score that has a p-value of [tex]\frac{1+\alpha}{2}[/tex].
The margin of error is:
[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
95% confidence level, hence[tex]\alpha = 0.95[/tex], z is the value of Z that has a p-value of [tex]\frac{1+0.95}{2} = 0.975[/tex], so [tex]z = 1.96[/tex].
For this problem, we consider that we want it to be within 4%.
Item a:
The sample size is n for which M = 0.04.There is no estimate, hence [tex]\pi = 0.5[/tex][tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
[tex]0.04 = 1.96\sqrt{\frac{0.5(0.5)}{n}}[/tex]
[tex]0.04\sqrt{n} = 1.96\sqrt{0.5(0.5)}[/tex]
[tex]\sqrt{n} = \frac{1.96\sqrt{0.5(0.5)}}{0.04}[/tex]
[tex](\sqrt{n})^2 = \left(\frac{1.96\sqrt{0.5(0.5)}}{0.04}\right)^2[/tex]
[tex]n = 600.25[/tex]
Rounding up:
A sample of 601 is needed.
Item b:
The estimate is [tex]\pi = 0.96[/tex], hence:
[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
[tex]0.04 = 1.96\sqrt{\frac{0.96(0.04)}{n}}[/tex]
[tex]0.04\sqrt{n} = 1.96\sqrt{0.96(0.04)}[/tex]
[tex]\sqrt{n} = \frac{1.96\sqrt{0.96(0.04)}}{0.04}[/tex]
[tex](\sqrt{n})^2 = \left(\frac{1.96\sqrt{0.96(0.04)}}{0.04}\right)^2[/tex]
[tex]n = 92.2[/tex]
Rounding up:
A sample of 93 is needed.
Item c:
The closer the estimate is to [tex]\pi = 0.5[/tex], the larger the sample size needed, hence, the correct option is A.
For more on the z-distribution, you can check brainly.com/question/25404151
A piece of wire 11 m long is cut into two pieces. One piece is bent into a square and the other is bent into an equilateral triangle. (a) How much wire should be used for the square in order to maximize the total area
Answer:
11 meters
Step-by-step explanation:
First, we can say that the square has a side length of x. The perimeter of the square is 4x, and that is how much wire goes into the square. To maximize the area, we should use all the wire possible, so the remaining wire goes into the triangle, or (11-4x).
The area of the square is x², and the area of an equilateral triangle with side length a is (√3/4)a². Next, 11-4x is equal to the perimeter of the triangle, and since it is equilateral, each side has (11-4x)/3 length. Plugging that in for a, we get the area of the equilateral triangle is
(√3/4)((11-4x)/3)²
= (√3/4)(11/3 - 4x/3)²
= (√3/4)(121/9 - 88x/9 + 16x²/9)
= (16√3/36)x² - (88√3/36)x + (121√3/36)
The total area is then
(16√3/36)x² - (88√3/36)x + (121√3/36) + x²
= (16√3/36 + 1)x² - (88√3/36)x + (121√3/36)
Because the coefficient for x² is positive, the parabola would open up and the derivative of the parabola would be the local minimum. Therefore, to find the maximum area, we need to go to the absolute minimum/maximum points of x (x=0 or x=2.75)
When x=0, each side of the triangle is 11/3 meters long and its area is
(√3/4)a² ≈ 5.82
When x=2.75, each side of the square is 2.75 meters long and its area is
2.75² = 7.5625
Therefore, a maximum is reached when x=2.75, or the wire used for the square is 2.75 * 4 = 11 meters
The length of the square must be 4 m in order to maximize the total area.
What are the maxima and minima of a function?When we put the differentiation of the given function as zero and find the value of the variable we get maxima and minima.
We have,
Length of the wire = 11 m
Let the length of the wire bent into a square = x.
The length of the wire bent into an equilateral triangle = (11 - x)
Now,
The perimeter of a square = 4 side
4 side = x
side = x/4
The perimeter of an equilateral triangle = 3 side
11 - x = 3 side
side = (11 - x)/3
Area of square = side²
Area of equilateral triangle = (√3/4) side²
Total area:
T = (x/4)² + √3/4 {(11 -x)/3}² _____(1)
Now,
To find the maximum we will differentiate (1)
dT/dx = 0
2x/4 + (√3/4) x 2(11 - x)/3 x -1 = 0
2x / 4 - (√3/4) x 2(11 - x)/3 = 0
2x/4 - (√3/6)(11 - x) = 0
2x / 4 = (√3/6)(11 - x)
√3x = 11 - x
√3x + x = 11
x (√3 + 1) = 11
x = 11 / (1.732 + 1)
x = 11/2.732
x = 4
Thus,
The length of the square must be 4 m in order to maximize the total area.
Learn more about maxima and minima here:
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The scores on an entrance exam to a university are known to have an approximately normal distribution with mean 65% and standard deviation 7.1%. What is the standardized score for a student who scores 60% on this test?
A. -0.70
B. 0.70
C. 1.88
D. -1.88
The midpoint of has coordinates of (4, -9). The endpoint A has coordinates (-3, -5). What are the coordinates of B?
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Answer:
(11, -13)
Step-by-step explanation:
If midpoint M is halfway between A and B:
M = (A +B)/2
Then B is ...
B = 2M -A
B = 2(4, -9) -(-3, -5) = (8+3, -18+5)
B = (11, -13)
Answer:
Use the midpoint formula:
[tex]midpoint=(\frac{x_{1}+x_{2}}{2}, \frac{y_{1}+y_{2}}{2})[/tex]
Endpoint A = (x₁, y₁) = (-3, -5)Endpoint B = (x₂, y₂)Midpoint = (4, -9)Substitute in the values:
[tex](4, -9)=(\frac{-3+x_{2}}{2} +\frac{-5+y_{2}}{2} )[/tex]
[tex]4=\frac{-3+x_{2}}{2} \\4(2)=-3+x_{2}\\8+3=x_{2}\\x_{2}=11[/tex] [tex]-9=\frac{-5+y_{2}}{2} \\(-9)(2)=-5+y_{2}\\-18+5=y_{2}\\y_{2}=-13[/tex]
Therefore, Point B = (11, -13)
) How many different three-letter initials can people have: , (b) How many different three-letter initials with none of the letters repeated can people have: , (c) How many different three-letter initials with letters repeated begin with an X: , (d) How many different three-letter initials begin with a F and end in a D:
Solution :
a).
The different three letter initials that people have is :
= 26 x 26 x 26
= [tex]26^3[/tex]
= [tex]17576[/tex]
b). The first place to be fill in26 ways.
The second place to be filled in 25 ways
The third place to be filled in 24 ways.
Therefore, total number of three letter initial with no repetition is :
= 26 x 25 x 24
= [tex]15600[/tex]
c). The total number of three letter initial begin with X = 1 x 26 x 26
= [tex]676[/tex]
d). The total number of the three letter initials that begin with letter 'F' an end with letter 'D' is = 1 x 26 x 1
= [tex]26[/tex]
A four digit password is a number that begins with a 3. If digits can be repeated how many possible passwords are there? show and explain your work
Answer:
The answer is 1,000
SInce the beginning number is 3 and there are ten possible numbers to put in the remaining three slots, there are exactly 1,000 possible combinations for a 3-digit code. The answer is 1,000. There are 3 rows of 10 digits. The number of combinations 10 to the thid power which is 1000 (10 * 10 * 10)
A researcher is interested in whether there is a significant difference between the mean age of marriage across three racial groups. Using the data provided below, conduct an F-test to determine whether you believe there is an association between race and average age at marriage.
Race N Mean
Black 113 25.39
White 904 22.99
Other 144 23.87
All Groups 1,161 23.33
Answer:
The P-value is < significance value ( 0.05 ) hence we reject the Null hypothesis ( i.e. There is an association between the race and average age at marriage )
Step-by-step explanation:
Conducting an F-test to determine association between race and average age at marriage
step 1 : State the hypothesis
H0 : ц1 = ц2 = ц3
Ha : ц1 ≠ ц2 ≠ ц3
step 2 : determine the mean square between
Given mean value of all groups = 23.33
SS btw = 113*(25.39 - 23.33)² + 904*(22.99 - 23.33)² + 144*(23.89 - 23.33)^2 = 113(4.2436) + 904(0.1156) + 144(0.3136)
= 629.1876
hence: df btw = 3 - 1 = 2
df total = 1161 - 1 = 1160
df within = 1160 - 2 = 1158
SS within = 36.87*1158 = 42695.46
Therefore the MS between = 629.19 / 2 = 314.60
The F-ratio = 314.59 / 36.87 = 8.53
using the values for Btw the P-value = 0.00021
The P-value is < significance value ( 0.05 ) hence we reject the Null hypothesis ( i.e. There is an association between the race and average age at marriage )
Mr. E bought 3 drinks and 5 sandwiches for $25.05 and Mr. E bought 4 drinks and 2 sandwiches $13.80. how much does each drink cost?
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Answer:
drink: $1.35sandwich: $4.20Step-by-step explanation:
Let d and s represent the cost of a drink and a sandwich, respectively. The two purchases give rise to the equations ...
3d +5s = 25.05
4d +2s = 13.80
Dividing the second equation by 2 gives ...
2d + s = 6.90
Subtracting the first equation from 5 times this, we get ...
5(2d +s) -(3d +5s) = 5(6.90) -25.05
7d = 34.50 -25.05 = 9.45
d = 1.35
The cost of each drink is $1.35.
__
Additional comment
Using the simplified 2nd equation, we can find the cost of a sandwich.
s = 6.90 -2d = 6.90 -2.70 = 4.20
The cost of each sandwich is $4.20.
Independent simple random samples are selected to test the difference between the means of two populations whose standard deviations are not known. We are unwilling to assume that the population variances are equal. The sample sizes are n1 = 25 and n2 = 35. The correct distribution to use is the:
1) t distribution with 59 degrees of freedom.
2) t distribution with 58 degrees of freedom.
3) t distribution with 61 degrees of freedom.
4) t distribution with 60 degrees of freedom.
Answer:
2) t distribution with 58 degrees of freedom.
Step-by-step explanation:
Population standard deviations not known:
This means that the t-distribution is used to solve this question.
The sample sizes are n1 = 25 and n2 = 35.
The number of degrees of freedom is the sum of the sample sizes subtracted by the number of samples, in this case 2. So
25 + 35 - 2 = 58 df.
Thus the correct answer is given by option 2.
Line JK passes through points J(–3, 11) and K(1, –3). What is the equation of line JK in standard form?
7x + 2y = –1
7x + 2y = 1
14x + 4y = –1
14x + 4y = 1
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Answer:
(b) 7x + 2y = 1
Step-by-step explanation:
You don't need to know how to find the equation. You just need to know how to determine if a point satisfies the equation. Try one of the points and see which equation fits. (The numbers are smaller for point K, so we prefer to use that one.)
7(1) +2(-3) = 1 ≠ -1 . . . . . tells you choice A doesn't work, and choice B does
The equation is ...
7x +2y = 1
__
Additional comment
The equations of choices C and D have coefficients with a common factor of 2. If the constant also had a factor of 2, we could say these equations are not in standard form, and we could reject them right away. Since the two points have integer values for x and y, we can reject these equations anyway: the sum of even numbers cannot be odd.
Answer:
b
Step-by-step explanation:
Determine whether the system of linear equations has one and only one solution, infinitely many solutions, or no solution. 5x − 6y = 4 10x − 12y = 8 one and only one solution infinitely many solutions no solution Correct: Your answer is correct. Find the solution, if one exists. (If there are infinitely many solutions, express x and y in terms of the parameter t. If there is no solution, enter NO SOLUTION.) (x, y) =
Answer:
same line infinite solutions
Step-by-step explanation:
5x − 6y = 4
10x − 12y = 8
10x − 12y = 8
10x − 12y = 8
0 = 0
same line infinite solutions
(A) A small business ships homemade candies to anywhere in the world. Suppose a random sample of 16 orders is selected and each is weighed. The sample mean was found to be 410 grams and the sample standard deviation was 40 grams. Find the 90% confidence interval for the mean weight of shipped homemade candies. (Round your final answers to the nearest hundredth)
(B) When 500 college students are randomly selected and surveyed; it is found that 155 own a car. Find a 90% confidence interval for the true proportion of all college students who own a car.
(Round your final answers to the nearest hundredth)
(C) Interpret the results (the interval) you got in (A) and (B)
The correct answer to the given question is "[tex]\bold{392.47\ < \mu <\ 427.53}[/tex],[tex]\bold{0.28 \ < P <\ 0.34}[/tex], and for Interpret results go to the C part.
Following are the solution to the given parts:
A)
[tex]\to \bold{(n) = 16}[/tex]
[tex]\to \bold{(\bar{X}) = 410}[/tex]
[tex]\to \bold{(\sigma) = 40}[/tex]
In the given question, we calculate [tex]90\%[/tex] of the confidence interval for the mean weight of shipped homemade candies that can be calculated as follows:
[tex]\to \bold{\bar{X} \pm t_{\frac{\alpha}{2}} \times \frac{S}{\sqrt{n}}}[/tex]
[tex]\to \bold{C.I= 0.90}\\\\\to \bold{(\alpha) = 1 - 0.90 = 0.10}\\\\ \to \bold{\frac{\alpha}{2} = \frac{0.10}{2} = 0.05}\\\\ \to \bold{(df) = n-1 = 16-1 = 15}\\\\[/tex]
Using the t table we calculate [tex]t_{ \frac{\alpha}{2}} = 1.753[/tex] When [tex]90\%[/tex] of the confidence interval:
[tex]\to \bold{410 \pm 1.753 \times \frac{40}{\sqrt{16}}}\\\\ \to \bold{410 \pm 17.53\\\\ \to392.47 < \mu < 427.53}[/tex]
So [tex]90\%[/tex] confidence interval for the mean weight of shipped homemade candies is between [tex]392.47\ \ and\ \ 427.53[/tex].
B)
[tex]\to \bold{(n) = 500}[/tex]
[tex]\to \bold{(X) = 155}[/tex]
[tex]\to \bold{(p') = \frac{X}{n} = \frac{155}{500} = 0.31}[/tex]
Here we need to calculate [tex]90\%[/tex] confidence interval for the true proportion of all college students who own a car which can be calculated as
[tex]\to \bold{p' \pm Z_{\frac{\alpha}{2}} \times \sqrt{\frac{p'(1-p')}{n}}}[/tex]
[tex]\to \bold{C.I= 0.90}[/tex]
[tex]\to\bold{ (\alpha) = 0.10}[/tex]
[tex]\to\bold{ \frac{\alpha}{2} = 0.05}[/tex]
Using the Z-table we found [tex]\bold{Z_{\frac{\alpha}{2}} = 1.645}[/tex]
therefore [tex]90\%[/tex] the confidence interval for the genuine proportion of college students who possess a car is
[tex]\to \bold{0.31 \pm 1.645\times \sqrt{\frac{0.31\times (1-0.31)}{500}}}\\\\ \to \bold{0.31 \pm 0.034}\\\\ \to \bold{0.276 < p < 0.344}[/tex]
So [tex]90\%[/tex] the confidence interval for the genuine proportion of college students who possess a car is between [tex]0.28 \ and\ 0.34.[/tex]
C)
In question A, We are [tex]90\%[/tex] certain that the weight of supplied homemade candies is between 392.47 grams and 427.53 grams.In question B, We are [tex]90\%[/tex] positive that the true percentage of college students who possess a car is between 0.28 and 0.34.Learn more about confidence intervals:
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Leonard made some muffins. He gave 5/8 of them to his grandmother and 10 muffins to his aunt. He then had 11 muffins left. How many muffins did he have at first?
Answer:
56
Step-by-step explanation:
x = number of muffins in total at the beginning.
x - 5/8 x - 10 = 11
x - 5/8 x = 21
8/8 x - 5/8 x = 21
3/8 x = 21
3x = 168
x = 56
Triangles ABC and DEF are similar. Find the
perimeter of triangle DEF.
a. 34.7 cm
b. 25.3 cm
c. 15 cm
d. 38 cm
Please show work to help me understand.
If Both triangles are similar the ratio of sides will be same
[tex]\\ \sf\longmapsto \dfrac{AB}{AC}=\dfrac{DE}{DF}[/tex]
[tex]\\ \sf\longmapsto \dfrac{8}{10}=\dfrac{12}{DF}[/tex]
[tex]\\ \sf\longmapsto 8DF=120[/tex]
[tex]\\ \sf\longmapsto DF=\dfrac{120}{8}[/tex]
[tex]\\ \sf\longmapsto DF=15cm[/tex]
Now
[tex]\\ \sf\longmapsto Perimeter=DF+DE+EF[/tex]
[tex]\\ \sf\longmapsto Perimeter=15+11+12[/tex]
[tex]\\ \sf\longmapsto Perimeter=38cm[/tex]
Find the missing side. Round your answer to the nearest tenth
Answer:
14.7
Step-by-step explanation:
tan(73)=48/x
or, x=48/tan(73)
or, x=14.7 (rounded to the nearest tenth)
Answered by GAUTHMATH
In a die game, you roll a standard 6-sided die twice. If the second number rolled is the same as the first number rolled, you win $25. Otherwise, you lose $2. If you were to play the game 100 times, how much money can you expect to make
Answer:
You can expect to make $250.
Step-by-step explanation:
Possible outcomes:
For the pair of dice:
(1,1), (1,2), (1,3), (1,4), (1,5), (1,6)
(2,1), (2,2), (2,3), (2,4), (2,5), (2,6)
(3,1), (3,2), (3,3), (3,4), (3,5), (3,6)
(4,1), (4,2), (4,3), (4,4), (4,5), (4,6)
(5,1), (5,2), (5,3), (5,4), (5,5), (5,6)
(6,1), (6,2), (6,3), (6,4), (6,5), (6,6)
So 36 total outcomes.
Probability of the second number rolled being the same as the first number rolled:
6 outcomes: (1,1), (2,2), (3,3), (4,4), (5,5), (6,6)
Out of 36, thus:
[tex]p = \frac{6}{36} = \frac{1}{6}[/tex]
Expected value of 1 game:
1/6 probability of earning $25.
5/6 probability of losing $2.
Thus:
[tex]E = 25\frac{1}{6} - 2\frac{5}{6} = \frac{25 - 10}{6} = 2.5[/tex]
100 games:
100*2.5 = 250
You can expect to make $250.
A number plus 16 times its reciprocal equals 8. Find all possible values for the number.
Answer:
4
Step-by-step explanation:
[tex]n+16\frac{1}{n} = 8\\\\n^2+16=8n\\n^2 -8n+16=0\\[/tex]Factorizing we get the answer 4
Let f(x) = -2x - 7 and g(x) = -4x + 6. Find. (F o G) (-5)
26
3
–59
–6
Answer:
-59
Step-by-step explanation:
f(x) = -2x - 7 and g(x) = -4x + 6.
f(g(x)) =
Replace x in the function f(x) with g(x)
= -2(-4x+6) -7
= 8x -12 -7
= 8x - 19
Let x = -5
f(g(-5) = 8(-5) -19
= -40 -19
= -59
A professor wondered if there was a difference in the proportion of students who dropped math classes between females and males. The professor randomly selected 20 math classes around campus and recorded the gender of the individual and whether or not a student enrolled in the class at the beginning of the term dropped the class at some point during the term. Assuming all conditions are satisfied, which of the following tests should the researcher use? Choose the correct answer below.
a) Chi-square goodness of fit test
b) two-sample z-test for proportions C
c) paired t-test
d) one-sample z-test for proportions
e) two-sample t-test
Answer:
b) two-sample z-test for proportions
Step-by-step explanation:
The most appropriate test to use for the research hypothesis stated above is the two sample z-test for proportions, this is because, the experiment has two independent groups (male and female) with the result of each group not affecting the result of the other. The experiment clearly stses that, it is to estimate the difference in proportion, hence, it is a test of proportions rather than mean. Also when performing, a two sample tests of proportion, the Z distribution is used.
data
find the range between 14, 15, 16, 14,23,13
15, 24, 12, 23, 14; 20, 17, 21, 22, 1031, 19, 20,
17, 16, 15, 11, 12, 21, 20, 17, 18, 19, 23
the lowest is 11 and the highest is 1031 then subtract it you are going to have 1020
Suppose (-13,2) is a point on the graph of y=f(x). What is a point that will be on the graph of y=9f(x)-5
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Answer:
(x, y') = (-13, 13)
Step-by-step explanation:
At the given value of x, f(x) = 2. Then 9f(x)-5 = 9(2) -5 = 13.
The point on the scaled, translated graph will be ...
(x, y') = (-13, 13)
_____
The graph shows a function f(x) with a distinct feature (vertex) at (-13, 2). It also shows where that distinct feature moves to when the function is scaled and translated.
One leg of a right angle has a length of 3m. The other sides have lengths
2^17+2^14 chia hết cho 9
Answer:
ABC
Step-by-step explanation:
= 2^14.2^3 + 2^14
= 2^14. (2^3 +1)
= 2^14 . 9
Vì 2^14.9 chia hết cho 9 nên 2^17 + 2^14 chia hết cho 9
(. là dấu nhân)
Answer:
đúng
Step-by-step explanation:
This answer was confusing for sure
Answer: lol ez
B.
Step-by-step explanation: XD
Answer:
D
Step-by-step explanation:
The general formula for the sine or cosine function is
y = A*Sin(Bx + C) + D
C = 0 in this case
B = pi / 3
The period is given by the formula
P = 2 * pi / B
P = 2 * pi//pi/3
The 2 pis cancel and you are left with 2*3 = 6
consider the differential equation x3y ''' + 8x2y '' + 9xy ' − 9y = 0; x, x−3, x−3 ln(x), (0, [infinity]). Verify that the given functions form a fundamental set of solutions of the differential equation on the indicated interval. The functions satisfy the differential equation and are linearly independent since W(x, x−3, x−3 ln(x)) = ≠ 0 for 0 < x < [infinity].
Verifying that a given expression is a solution to the equation is just a matter of plugging in the expression and its derivatives, and making sure that the given expressions are indeed linearly independent.
For example, if y = x, then y' = 1 and the other derivatives vanish. So the DE after substitution reduces to
9x - 9x = 0
which is true for all 0 < x < ∞.
To check for linear independence, you compute the Wronskian, which, judging by what you wrote, you've already done...
Solve 3(5x + 7) = 9x + 39.
O A. X=-3
B. X= -10
O c. x = 10
O D. x= 3
Answer:
x=3
Step-by-step explanation:
3(5x + 7) = 9x + 39
15x + 21 = 9x + 39
15x - 9x = 39 - 21
6x = 18
x = 3
The triangles are similar, find y
Answer:
y = 3.6
x = 3.5
Step-by-step explanation:
The triangles are similar.
[tex]\frac{3}{2.4} = \frac{x}{2.8} = \frac{4.5}{y}[/tex]
Find y:
[tex]\frac{4.5}{y} = \frac{5}{4}[/tex]
[tex]4.5 * 4 = 5y => 18 = 5y => y = 3.6[/tex]
Find x:
[tex]\frac{x}{2.8} = \frac{5}{4}[/tex]
[tex]2.8 * 5 = 4x => 14 = 4x => x = 3.5[/tex]
Question 7
In circle P below, angle OPM equals 124 degrees and line segments ON and MN are tangents to the circle
What is the measure of Angle ONM?
A 56
B 62
С 74
D 90
Answer:
B) 62 is the answer. I'm sure
I need to know this answe ASAP
Answer:
The function is always increasing
Step-by-step explanation:
To be increasing, the y value needs to be getting bigger as x gets bigger
This is true for all values of x
The function is increasing for all values of x
Find the slope of the line (4,0) (9,11) Help plsss!!!!
Answer:
m= 11/5 (11 over 5)
Hope this helps! :)
the graph of f(x)=6(.25)^x and its reflection across the y-axis , g(x), are shown. what is the domain of g(x)
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Answer:
all real numbers
Step-by-step explanation:
The domain of any exponential function is "all real numbers". Reflecting the graph across the y-axis, by replacing x by -x does not change that.
The domain of g(x) = f(-x) is all real numbers.
