A consumer advocate agency is concerned about reported failures of two brands of MP3 players, which we will label Brand A and Brand B. In a random sample of 197 Brand A players, 33 units failed within 1 year of purchase. Of the 290 Brand B players, 25 units were reported to have failed within the first year following purchase. The agency is interested in the difference between the population proportions, , for the two brands. Using the data from the two brands, what would be the standard error of the estimated difference, Dp = A – B, if it were believed that the two population proportions were, in fact, equal (i.e., )?
Answer:
The standard error of the estimated difference is of 0.0313.
Step-by-step explanation:
To solve this question, we need to understand the central limit theorem, and subtraction of normal variables.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
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]
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
Brand A:
33 out of 197, so:
[tex]p_A = \frac{33}{197} = 0.1675[/tex]
[tex]s_A = \sqrt{\frac{0.1675*0.8325}{197}} = 0.0266[/tex]
Brand B:
25 out of 290, so:
[tex]p_B = \frac{25}{290} = 0.0862[/tex]
[tex]s_B = \sqrt{\frac{0.0862*0.9138}{290}} = 0.0165[/tex]
What would be the standard error of the estimated difference?
[tex]s = \sqrt{s_A^2+s_B^2} = \sqrt{0.0266^2+0.0165^2} = 0.0313[/tex]
The standard error of the estimated difference is of 0.0313.
The acute angle of the right angle triangle are in the ratio of 4:5
Answer:
Since the triangle is a right angled triangle, one of the angles is 90°. In the right angled triangle, the acute angles are in the ratio 4:5. Let the measures of the acute angles of the triangle in degrees be 4k and 5k, where k is a constant.
Step-by-step explanation:
hope it helps.
Answer:
40and50
Step-by-step explanation:
let the acute angles be 4x and 5x then,
4x+5x+90=180 [sum of all angles of a right angled triangle]
or,9x=180-90
or,x=90/9
x=10
4x=4×10=40
5x=5×10=50
Consider this equation. √x - 1 - 5 = x - 8 The equation has(two valid solutions, one valid solution) and(one extraneous solution, no extraneous solutions) A valid solution for x is(0, 4, 2, 5)
The equation has 2 valid solutions; no extraneous solutions
The given equation is:
[tex]\sqrt{x - 1} - 5= x - 8[/tex]
First, we determine the solutions
[tex]\sqrt{x - 1} - 5= x - 8[/tex]
Add 5 to both sides
[tex]\sqrt{x - 1} = x - 8 + 5[/tex]
[tex]\sqrt{x - 1} = x - 3[/tex]
Square both sides
[tex]x - 1 = (x - 3)^2[/tex]
Expand
[tex]x - 1 = x^2- 3x - 3x + 9[/tex]
[tex]x - 1 = x^2- 6x + 9[/tex]
Collect like terms
[tex]x^2 - 6x - x + 9 + 1 = 0[/tex]
[tex]x^2 - 7x + 10 = 0[/tex]
Expand again
[tex]x^2 - 2x-5x + 10 = 0[/tex]
Factorize
[tex]x(x - 2) -5(x -2)= 0[/tex]
Factor out x - 2
[tex](x - 5)(x -2)= 0[/tex]
Split
[tex]x - 5=0[/tex] or [tex]x - 2 = 0[/tex]
[tex]x= 5[/tex] or [tex]x = 2[/tex]
The above values are valid values of x.
Hence, the equation has 2 valid solutions; no extraneous solutions
Read more about equations at:
https://brainly.com/question/2396830
Answer:
That person is wrong, First blank is : one valid solution , Second blank is : one extraneous solution, and I'm not sure what the 3rd blank is but I think It's 4.
Step-by-step explanation:
for plato users
Study the scatterplot and trend line. Which two points can be used to find the equation of the trend line?
Which points are on the trend line?
(1, 30) and (9, 95)
(2, 30) and (6, 70)
(2, 45) and (8, 90)
(3, 50) and (7, 65)
Answer:
C
Step-by-step explanation:
Just trust
Answer:
C
Step-by-step explanation:
I did the assignment in edge and got it right.
Proof:
Simplify: −4(b+6)−2b(1−4b
Step-by-step explanation:
-4b-24-2b+8b2
8b2-6b-24=0
what is the absolute value of |9|?
Answer:
9
Step-by-step explanation:
it's as simple as that 9 is 9 away from 0
A circular fence is being placed to surround a tree. The diameter of the
fence is 4 feet. How much fencing is used? *
Answer:
12.6 ft
Step-by-step explanation:
14. What, if any, is a real solution to 5x +1 +9 - 3?
1
C
D. There is no real solution.
I believe the question is:
What is the solution to 5x + 1 +9 - 3
In this case, we solve for X.
5x + 1 + 9 - 3
5x + 10 - 3
5x + 7
5x = -7
x = -7/5
Unfortunately, It is not one of the answer choices it looks like.
Maybe you should reword your question but hopefully this is correct.
If you meant to say 5x+1 + 9 < 3 --> 5x + 10 < 3 --> 5x < -7 --> x < -7/5
The value of x in a given expression is -7/5.
We have given that,
5x + 1 + 9 - 3
We have to determine the value of x.
What is the variable?A variable is any factor, trait, or condition that can exist in differing amounts or types. Scientists try to figure out how the natural world works
In this case, we solve for X.
5x + 1 + 9 - 3
5x + 10 - 3
5x + 7
5x = -7
x = -7/5
If you meant to say 5x+1 + 9 < 3 --> 5x + 10 < 3 --> 5x < -7 --> x < -7/5.
Therefore we get the value of x is -7/5.
To learn more about the value of the variable visit:
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The population of a city increased from 23,400 to 27,800 between 2008 and 2012. Find the change of population per year if we assume the change was constant from 2008 to 2012.
Find the amount of the increase:
27800 - 23400 = 4,400
Find number of years: 2012 - 2008 = 4 years
Divide amount of change by number of years:
4,400 / 4 = 1,100 people per year.
In an experiment, you choose to have two randomly assigned groups. In one, you take measurements both pretest and posttest; with the second, a posttest-only measure. This describes which task of conducting an experiment
Answer:
The answer is "Specific treatment levels".
Step-by-step explanation:
When we experimenting with 'level' which is related to the quantity or magnitude of treatment. For this part of an experiment or study, a group or individual is exposed to a specified set of circumstances. For example: If four categories are exposed to different doses of a given drug, then each dose reflects a level of a treatment factor in the model.
Which of the following choices is equivalent to the equation below?
5(2x−1) = 5(5x−14)
A 2x − 1 = 5x − 14
B 5(2x − 1) = 5x − 14
C 2x − 1 = 5
D None of these choices are correct.
Answer:
2x-1 = 5x-14
Step-by-step explanation:
5(2x−1) = 5(5x−14)
Divide each side by 5
5/5(2x−1) = 5/5(5x−14)
2x-1 = 5x-14
Answer:
A.
Step-by-step explanation:
5(2x−1) = 5(5x−14)
10x - 5 = 25x - 70
65 = 15x
x = 13/3.
Take Option A.
2x - 1 = 5x - 14
3x = 13
x = 13/3 so its this one.
B: 10x - 5 = 5x - 14
5x = -9
x = -9/5 so NOT B.
C. simplifies to x = 3. so NOT C.
Nasa is building a satellite that is roughly the shape of a sphere. If the satellite weighs 14.25 pounds per cubic foot before the launch and has a diameter of 4.7 feet. What is the total weight in pounds?
Answer:
Step-by-step explanation:
A superhero can fly from New York to Los Angeles in 30 minutes. The distance from New York to Los Angeles is approximately 2,450 miles.
How many miles per hour is the superhero flying?
Work Shown:
30 min = 30/60 = 0.5 hours
distance = rate*time
rate = distance/time
rate = (2450 miles)/(0.5 hours)
rate = (2450/0.5) mph
rate = 4900 mph
For the sake of comparison, a typical commercial passenger jet can reach max speeds of about 600 mph.
a store sign reads "Take 75% of the original price when you take an additional 15% off the sale price, which is 60% off the original price." Is the stores sign accurate?
Answer:
The new price is 66% off the original not 75% off
Step-by-step explanation:
Let x be the original price
First take 60 percent off
x - x*60% = new price
x- .60x = .40x
The new price is .40x
Then take 15 % off
(.40x) - (.40x)*15%
.40x - .40x*.15
.40x - .06x
.34x
100 -.34 =.66
The new price is 66% off the original not 75% off
Show why (2×3×7)^4 = 2^4 × 3^4 × 7^4 show work
[tex] {a}^{m} \times {b}^{m} = ( {ab)}^{m} [/tex]
(2×3×7)⁴=(2×3)⁴×7⁴(2×3×7)⁴=(2×3×7)⁴RHS=LHSplease mark this answer as brainlist
CHứng minh rằng trong hệ g - phân với 2
1/10 + 3/5
ANSWER QUICK PLS FIRST ANSWER GETS BRAINLIEST
T
On Melissa's 6th birthday, she gets a $2000 CD that earns 5% interest, compounded semiannually. If the
CD matures on her 16th birthday, how much money will be available?
TE
$
(S
9514 1404 393
Answer:
$3277.23
Step-by-step explanation:
The future value of the CD with interest at rate r compounded semiannually for t years will be given by ...
A = P(1 +r/2)^(2t)
where P is the principal value.
For the given rate and time, this is ...
A = $2000(1 +0.05/2)^(2·10) = $2000(1.025^20) ≈ $3277.23
The value of the CD at maturity will be $3277.23.
If a=120° , find the measure of angles b, c and d.
Explain your reasoning.
Answer:
b=120°
c=60°
d=60°
SEE THE IMAGE FOR SOLUTION
Write a rule to describe the transformation.
A. reflection across y=x
B. rotation 90º clockwise about the origin
C. rotation 180º about the origin
D. rotation 90º counterclockwise about the origin
Answer:
C. rotation 180º about the origin
Step-by-step explanation:
Given
Quadrilaterals GWVY and G'W'V'Y'
Required
Describe the transformation rule
Pick points Y and Y'
[tex]Y = (5,-4)[/tex]
[tex]Y' = (-5,4)[/tex]
The above obeys the following rule:
[tex](x,y) \to (-x,-y)[/tex]
When a point is rotated by 180 degrees, the rule is:
[tex](x,y) \to (-x,-y)[/tex]
Hence, (c) is correct
Algebra 2, please help! thank you
The function y = 2 cos 3(x + 2π∕3) +1 has a phase shift (or horizontal shift) of
A) –2π∕3
B) 3
C) 1
D) 2
Answer:
-2pi/3
Step-by-step explanation:
y = 2 cos 3(x + 2π∕3) +1
y = A sin(B(x + C)) + D
amplitude is A
period is 2π/B
phase shift is C (positive is to the left)
vertical shift is D
We have a shift to the left of 2 pi /3
Answer:
A
Step-by-step explanation:
The standard cosine function has the form:
[tex]\displaystyle y = a\cos (b(x-c)) + d[/tex]
Where |a| is the amplitude, 2π / b is the period, c is the phase shift, and d is the vertical shift.
We have the function:
[tex]\displaystyle y = 2 \cos 3\left(x + \frac{2\pi}{3}\right) + 1[/tex]
We can rewrite this as:
[tex]\displaystyle y = \left(2\right)\cos 3\left(x - \left(-\frac{2\pi}{3}\right)\right) + 1[/tex]
Therefore, a = 2, b = 3, c = -2π/3, and d = 1.
Our phase shift is represented by c. Thus, the phase shift is -2π/3.
Our answer is A.
Assume a researcher wants to compare the mean Alanine Aminotransferase (ALT) levels in two populations, individuals who drink alcohol and individuals who do not drink alcohol. The mean ALT levels for the individuals who do not drink alcohol is 32 with a standard deviation of 14, and 37 individuals were in the sample. The mean ALT levels for individuals who drink alcohol is 69 with a standard deviation of 19, and 38 individuals were in the sample. Construct and interpret a 95% confidence interval demonstrating the difference in means for those individuals who drink alcohol when compared to those who do not drink alcohol.
a. The researchers are 95% confident that the true mean difference in ALT values between the population of drinkers and population of non-drinkers is between 24.22 and 39.78.
b. The researchers are 95% confident that the true mean difference in ALT values between the population of drinkers and population of non-drinkers is between 24.33 and 39.67
c. The researchers are 95% confident that the true mean difference in ALT values between the population of drinkers and population of non-drinkers is between 24.32 and 39.68.
d. The researchers are 95% confident that the true mean difference in ALT values between the population of drinkers and population of non-drinkers is between 24.41 and 39.59.
Answer:
c. The researchers are 95% confident that the true mean difference in ALT values between the population of drinkers and population of non-drinkers is between 24.32 and 39.68.
Step-by-step explanation:
Given :
Groups:
x1 = 69 ; s1 = 19 ; n1 = 38
x2 = 32 ; s2 = 14 ; n2 = 37
1 - α = 1 - 0.95 = 0.05
Using a confidence interval calculator to save computation time, kindly plug the values into the calculator :
The confidence interval obtained is :
(24.32 ; 39.68) ; This means that we are 95% confident that the true mean difference in ALT values between the two population lies between
(24.32 ; 39.68) .
If g(x) = x^2 + 8x - 24 find the value of g(6)
Answer:
hope it helps you..........
Answer:
60
Step-by-step explanation:
g(x)= x^2 +8x - 24
Substitute x for 6 in the equation
g(6)= 6^2 + 8(6) - 24
= 36+48-24
= 60
What is the product of 2/5 × 3/4?
Answer:
3/10
Step-by-step explanation:
2/5*3*4
=6/20
=3/10
Solve for x
Answer choices:
4
5
8
3
2
opposite angles are equal
[tex]\\ \sf\longmapsto 13x+19=84[/tex]
[tex]\\ \sf\longmapsto 13x=84-19[/tex]
[tex]\\ \sf\longmapsto 13x=65[/tex]
[tex]\\ \sf\longmapsto x=\dfrac{65}{13}[/tex]
[tex]\\ \sf\longmapsto x=5[/tex]
Answer:
[tex]\boxed {\boxed {\sf x=5}}[/tex]
Step-by-step explanation:
We are asked to solve for x.
We are given a pair of intersecting lines and 2 angles measuring (13x+19)° and 84°. The angles are opposite each other, so they are vertical angles. This means they are congruent or have the same angle measure.
Since the 2 angles are congruent, we can set them equal to each other.
[tex](13x+19)=84[/tex]
Solve for x by isolating the variable. This is done by performing inverse operations.
19 is being added to 13x. The inverse operation of addition is subtraction. Subtract 19 from both sides of the equation.
[tex]13x+19-19= 84 -19[/tex]
[tex]13x= 84 -19[/tex]
[tex]13x=65[/tex]
x is being multiplied by 13. The inverse operation of multiplication is division. Divide both sides by 13.
[tex]\frac {13x}{13}= \frac{65}{13}[/tex]
[tex]x= \frac{65}{13}[/tex]
[tex]x= 5[/tex]
For this pair of vertical angles, x is equal to 5.
What is the volume of this rectangular pyramid?
_____ cubic millimeters
Answer:
Step-by-step explanation:
L = 9 mm
W = 9 mm
H = 10 mm
volume = LWH/3 = 9·9·10/3 = 270 mm³
-36 = 6(2-8n) please
Answer:
n=1
Step-by-step explanation:
-36 = 6(2-8n)
-36=12-48n
-36-12=-48n
-48=-48n
n=1
Find the sum of -3x^2-4x+3 2x^2+3
One angle of an isosceles triangle is 16 what are the other 2 angles
Answer:
other two angle will be
82
as 82+82+16 = 180'
People were asked if they owned an artificial Christmas tree. Of 78 people who lived in an apartment, 38 own an artificial Christmas tree. Also it was learned that of 84 people who own their home, 46 own an artificial Christmas tree. Is there a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees
Answer:
The p-value of the test is 0.4414, higher than the standard significance level of 0.05, which means that there is not a a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees.
Step-by-step explanation:
Before testing the hypothesis, we need to understand the central limit theorem and subtraction of normal variables.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
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]
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
Apartment:
38 out of 78, so:
[tex]p_A = \frac{38}{78} = 0.4872[/tex]
[tex]s_A = \sqrt{\frac{0.4872*0.5128}{78}} = 0.0566[/tex]
Home:
46 out of 84, so:
[tex]p_H = \frac{46}{84} = 0.5476[/tex]
[tex]s_H = \sqrt{\frac{0.5476*0.4524}{84}} = 0.0543[/tex]
Test if the there a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees:
At the null hypothesis, we test if there is no difference, that is, the subtraction of the proportions is equal to 0, so:
[tex]H_0: p_A - p_H = 0[/tex]
At the alternative hypothesis, we test if there is a difference, that is, the subtraction of the proportions is different of 0, so:
[tex]H_1: p_A - p_H \neq 0[/tex]
The test statistic is:
[tex]z = \frac{X - \mu}{s}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, and s is the standard error.
0 is tested at the null hypothesis:
This means that [tex]\mu = 0[/tex]
From the samples:
[tex]X = p_A - p_H = 0.4872 - 0.5476 = -0.0604[/tex]
[tex]s = \sqrt{s_A^2 + s_H^2} = \sqrt{0.0566^2 + 0.0543^2} = 0.0784[/tex]
Value of the test statistic:
[tex]z = \frac{X - \mu}{s}[/tex]
[tex]z = \frac{-0.0604 - 0}{0.0784}[/tex]
[tex]z = -0.77[/tex]
P-value of the test and decision:
The p-value of the test is the probability of the difference being of at least 0.0604, to either side, plus or minus, which is P(|z| > 0.77), given by 2 multiplied by the p-value of z = -0.77.
Looking at the z-table, z = -0.77 has a p-value of 0.2207.
2*0.2207 = 0.4414
The p-value of the test is 0.4414, higher than the standard significance level of 0.05, which means that there is not a a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees.
