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., )?

Answers

Answer 1

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.


Related Questions

∫[tex]\frac{x+2019}{x^{2}+9 }[/tex]

Answers

Split up the integral:

[tex]\displaystyle\int\frac{x+2019}{x^2+9}\,\mathrm dx = \int\frac{x}{x^2+9}\,\mathrm dx + \int\frac{2019}{x^2+9}\,\mathrm dx[/tex]

For the first integral, substitute y = x ² + 9 and dy = 2x dx. For the second integral, take x = 3 tan(z) and dx = 3 sec²(z) dz. Then you get

[tex]\displaystyle \int\frac x{x^2+9}\,\mathrm dx = \frac12\int{2x}{x^2+9}\,\mathrm dx \\\\ = \frac12\int\frac{\mathrm du}u \\\\ = \frac12\ln|u| + C \\\\ =\frac12\ln\left(x^2+9\right)[/tex]

and

[tex]\displaystyle \int\frac{2019}{x^2+9}\,\mathrm dx = 2019\int\frac{3\sec^2(z)}{(3\tan(z))^2+9}\,\mathrm dz \\\\ = 2019\int\frac{3\sec^2(z)}{9\tan^2(z)+9}\,\mathrm dz \\\\ = 673\int\frac{\sec^2(z)}{\tan^2(z)+1}\,\mathrm dz \\\\ = 673\int\frac{\sec^2(z)}{\sec^2(z)}\,\mathrm dz \\\\ = 673\int\mathrm dz \\\\ = 673z+C \\\\ = 673\arctan\left(\frac x3\right)+C[/tex]

Then

[tex]\displaystyle\int\frac{x+2019}{x^2+9}\,\mathrm dx = \boxed{\frac12\ln\left(x^2+9\right) + 673\arctan\left(\frac x3\right) + C}[/tex]

HELPPPP PLZ
Witch statement is true about the value of |6|?

Answers

Answer:

The third choice is the correct one.

Step-by-step explanation:

The absolute value of six means that it's the distance from 0 to six, and that distance will be positive regardless of the number being negative or not.

Answer: The third answer is correct

Step-by-step explanation:

Since |6| is the absolute value of positive six, the value of an absolute value of any number is always positive.

Simone invests $2,000 in an account that compounds interest quarterly and earns 9%. How many years will it take for his money to double? (Round your answer to one decimal place.)

Answers

no te puedo contestarte yo no hablo inglés

Write the complies number z=3-3i in trigonometric form

Answers

Answer:

3*sqrt(2) and 3pi/4

Step-by-step explanation:

tan(theta)=y/x and r^2=y^+x^2.

tan(theta)=-3/3=-1, theta=3pi/4

r=sqrt(3^2+3^2)=3*sqrt(2)

help fast I'm dum
and I'm sorry if I keep spamming this.


Curtis types 48 words in 1 minute how many words does Curtis type in 8 minutes? use the following equivalent rates to help solve the problem. how many words does Curtis type in 8 minutes? ​

Answers

Answer:

384

Step-by-step explanation:

Answer:

384 words

Step-by-step explanation:

Number of words typed in 1 minute = 48

So, number of words typed in 8 minutes

= Number of words typed in 1 minute × 8

= 48 × 8

= 384

So, Curtis types 384 words in 8 minutes.

A poll of 2,060 randomly selected adults showed that 89% of them own cell phones. The technology display below results from a test of the claim that 91% of adults own cell phones. Use the normal distribution as an approximation to the binomial distribution, and assume a 0.01 significance level to complete parts (a) through (e).
Test of p=0.91 vs p≠0.91
Sample X N Sample p 95% CI Z-Value p-Value
1 1833
2,060 0.889806 ( 0.872035 , 0.907577 ) ~ 3.20 0.001
a. Is the test two-tailed, left-tailed, or right-tailed?∙
Left-tailed test∙
Two-tailed test∙
Right tailed test
b. What is the test statistic?
The test statistic is _____ (Round to two decimal places as needed.)
c. What is the P-value?
The P-value is _____ (Round to three decimal places as needed.)
d. What is the null hypothesis and what do you conclude about it?
Identify the null hypothesis.
A. H0:p<0.91∙
B. H0:p≠0.91∙
C. H0:p>0.91∙
D. H0:p=0.91.

Answers

Answer:

Two tailed test

Test statistic = 3.20

Pvalue = 0.001

H1 : p ≠ 0.91

Step-by-step explanation:

Given :

Test of p=0.91 vs p≠0.91

The use if not equal to ≠ sign in the null means we have a tow tailed test, which means a difference exists in the proportion which could be lesser or greater than the stated population proportion.

The test statistic :

This is the Z value from the table given = 3.20

The Pvalue = 0.001

Since Pvalue < α ;Reject H0

y=4.5x+13.45 y=6x-4.55

Answers

Step-by-step explanation:

Solve for the first variable in one of the equations, then substitute the result into the other equation.

Point Form:

(

12

,

67.45

)

Equation Form:

x

=

12

,

y

=

67.45

Use the discriminant to determine the number of solutions to the quadratic equation −40m2+10m−1=0

Answers

From the analysis of the discriminant, you obtain that the quadratic function has no real solutions.

In first place, you must know that the roots or solutions of a quadratic function are those values ​​of x for which the expression is 0. This is the values ​​of x such that y = 0. That is, f (x) = 0.

Being the quadratic function f (x)=a*x² + b*x + c, then the solution must be when: 0 =a*x² + b*x + c

The solutions of a quadratic equation can be calculated with the quadratic formula:

[tex]Solutions=\frac{-b+-\sqrt{b^{2} -4*a*c} }{2*a}[/tex]

The discriminant is the part of the quadratic formula under the square root, that is, b² - 4*a*c

The discriminant can be positive, zero or negative and this determines how many solutions (or roots) there are for the given quadratic equation.

If the discriminant:

is positive: the quadratic function has two different real solutions. equal to zero: the quadratic function has a real solution. is negative: none of the solutions are real numbers. That is, it has no real solutions.

In this case, a= -40, b=10 and c= -1. Then, replacing in the discriminant expression:

discriminant= 10² -4*(-40)*(-1)

Solving:

discriminant= 100 - 160

discriminant= -60

The discriminant is negative, so the quadratic function has no real solutions.

Primo car rental agency charges $21 per day plus $0.20 por milo. Ultimo car rental agency charges $24 per day plus $1.00 per milo. Find the daily mileage for which the Ultimo charge is four times the Primo charge.
The mileage is

Answers

Answer:

300 miles

Step-by-step explanation:

Let us consider the miles they travelled is 'm'

Mileage for Primo= 21 + (m × 0.20) = 21+0.2m

Mileage for Ultimo= 24+ ( m× 1.00) = 24 + m

Question says The mileage is equal when Ultimo's charge is 4× Primo

Thus,

4 × (21+0.2m) = 24+ m

84 + 0.8m = 24 + m

60 = 0.2m

m = 300

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

Answers

9514 1404 393

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:

Can someone help me with this?

Answers

Answer:

183.3 in^3

Step-by-step explanation:

Find the volume of the rectangular bottom

V = l*w*h

V = 5*5*6 =150 in^3

Find the volume of the triangular pyramid

V = 1/3 Bh where B is the area of the base and h is the height

V = 1/3 ( 5*5) * 4 = 100/3

Add the two volumes together

150 + 100/3

150 +33.3

183.3 in^3

2. Solve the following system of equations. y = 5 + x 2x + 2y = 30

Answers

x = 5

since we know y= 5 + x , plug this into y in the second equation.

2x + 2 (5 + x) = 30

distribute 2 into the 5 and x

2x + 10 + 2x = 30

combine like terms

4x + 10 = 30

subtract 10 from both sides

4x = 20

divide four by both sides to isolate the variable

x = 5
Answer is d 1+2 y=5 add all cards

Please help! Question and answers are in the pic

Answers

So far she worked 4 days at 5 1/2 hours a day for a total of 22 hours.

22 hours x $8.50 = $187

Subtract that from the cost of the computer:

899-187 = $712

She needs $712 more.

Amount she makes per shift: $8.50 x 5 1/2 hours = $46.75

Divide what she needs by amount per shift:

712 / 46.75 = 15.22 shifts

She needs to work 16 more shifts.

any equations that equal three?

Answers

0+3=3 so I hope that helps
1•3=3 or 4-1=3 try those equations

urgent image below for the question

Answers

Answer:

240 ft²

Step-by-step explanation:

Surface area of a rectangular prism is,

2(lw+wh+hl)

= 2(7×6+6×6+6×7)

= 240 ft²

pLEASE help best and right answer gets brainliest

Answers

1) is 9
2) is 2

Absolute value of a number is the distance a number is from 0.

Step-by-step explanation:

| - 5 | + | - 4 |

5 + 4

= 9

| - 6| - 4

6 - 4

2

I hope this answers your question.

The correlation coefficient, r, between the prices of smartphones, x, and the number of sales of phones, y, equals −0.63.


Select the statement which best describes the relationship between the price and sales.


The value of r indicates that the number of sales decreases as the price decreases.

The value of r indicates that the number of sales decreases as the price stays the same.

The value of r indicates that the number of sales decreases as the price increases.

The value of r indicates that the number of sales is not related to the price.


I think its (C): The value of r indicates that the number of sales decreases as the price increases.

Answers

Answer:

(C) The value of r indicates that the number of sales decreases as the price increases.

ED2021.

The best statement, given the correlation coefficient of -0.63 is: value of r indicates that the number of sales decreases as the price increases.

What is a Negative Correlation Coefficient?

A negative correlation coefficient has a negative sign, and implies a negative relationship between two variables.

This means that, as one variable decreases, the other variable increases.

Thus, a correlation coefficient of -0.63 shows a negative relationship between prices of smartphones and the number of sales.

Therefore, the best statement, given the correlation coefficient of -0.63 is: value of r indicates that the number of sales decreases as the price increases.

Learn more about correlation coefficient on:

https://brainly.com/question/4219149

During a particularly dry growing season in a southern state, farmers noticed that there is a delicate balance between the number of seeds that are planted per square foot and the yield of the crop in pounds per square foot. The yields were the smallest when the number of seeds per square foot was either very small or very large.

What is the explanatory variable for this relationship?

yield of the crop
location of the farm
precipitation for the growing season
number of seeds planted per square foot

I think it's (D).
number of seeds planted per sf

Answers

Answer:

The guy above me is correct

Step-by-step explanation:

2022

Answer:

number of seeds planted per square foot

Step-by-step explanation:

response is the yield explained by how many seeds are planted

find the surface area of the triangular prism below.

Answers

Step-by-step explanation:

At first you need to take its lateral surface area by using the perimeter of base of the triangle and the height of prism.

Then after calculating it you need to find out its total surface area which is asked in the question and that is calculated by adding the area of both triangles of the prism in the lateral surface area.

Then that's your answer.

9514 1404 393

Answer:

  544 square units

Step-by-step explanation:

The surface area is the sum of the area of the two triangular bases and the three rectangular faces. The relevant area formulas are ...

  A = 1/2bh . . . . area of a triangle with base b and height h

  A = LW . . . . . are of a rectangle of length L and width W

__

  SA = 2(1/2)(12)(8) + (10 +10 +12)(14)

  SA = 96 +448 = 544 . . . square units

what is the volume of the container

Answers

Answer:

600 cubic inches

Step-by-step explanation:

V = l • w • h

V = 12 • 5 • 10

V = 600 cubic inches

At a time hours after taking a tablet, the rate at which a drug is being eliminated r(t)= 50 (e^-01t - e^-0.20t)is mg/hr. Assuming that all the drug is eventually eliminated, calculate the original dose.

Answers

Answer:

2500 mg

Step-by-step explanation:

Since r(t) is the rate at which the drug is being eliminated, we integrate r(t) with t from 0 to ∞ to find the original dose of drug, m. Since all of the drug will be eliminated at time t = ∞.

Since r(t) =  50 (e^-01t - e^-0.20t)

m = ∫₀⁰⁰50 (e^-01t - e^-0.20t)

= 50∫₀⁰⁰(e^-01t - e^-0.20t)

= 50[∫₀⁰⁰e^-01t - ∫₀⁰⁰e^-0.20t]

= 50([e^-01t/-0.01]₀⁰⁰ - [e^-0.20t/-0.02]₀⁰⁰)

= 50(1/-0.01[e^-01(∞) - e^-01(0)] - {1/-0.02[e^-0.02(∞) - e^-0.02(0)]})

= 50(1/-0.01[e^-(∞) - e^-(0)] - {1/-0.02[e^-(∞) - e^-(0)]})

= 50(1/-0.01[0 - 1] - {1/-0.02[0 - 1]})

= 50(1/-0.01[- 1] - {1/-0.02[- 1]})

= 50(1/0.01 - 1/0.02)

= 50(100 - 50)

= 50(50)

= 2500 mg

Please help me to find this answer

Answers

Answer:

37

Step-by-step explanation:

Tan(B) = 6/8

B= arctan(3/4)=37

Put the following equation of a line into slope-intercept form, simplifying all
fractions.
3x – 9y = -72

Answers

24+-3y is the correct answer

the slope-intercept form of the given equation is y = x/3 + 8.

What is the slope?

The increase divided by the run, or the ratio of the rise to the run is known as the line's slope. The coordinate plane describes the slope of the line.

The slope-intercept form of a line is Y = m*X +C.

Given an equation 3x-9y = -72, which we will try to make in the slope-intercept form by using simplification.

3x-9y = -72

9y = 3x + 72

y = 1/3 * x + 8

Therefore y = x/3 + 8 is the slope-intercept form of the given equation.  where its slope is 1/3.

Learn more about slope here:

https://brainly.com/question/3605446

#SPJ2

Mark earns $47,800 a year working for a delivery service. He is single and pays $2,152.60 in state income tax each year. He claims no dependents. What is the tax rate of Mark’s state he lives in?

Answers

Answer:

4.5%

Step-by-step explanation:

The tax rate=(2152.6/47800)*100=4.5%

Draw the line segment with endpoints (-5, 9) and (-1, -7) and find the value of y if x=-4;-2.5;-2;-1.5;0 plz answer asap

Answers

Answer:

5, - 1, - 3, - 5, - 11

Step-by-step explanation:

The equation of the line is y=-4x-11. The y values corresponding to x are 5, - 1, - 3, - 5, - 11

Solve this inequality: x+ 4< 16

Answers

Answer:

x < 12

Step-by-step explanation:

subtract 4 from both sides:

x + 4 < 16

   - 4     -4

x < 12

Answer:

x<4

Step-by-step explanation:

x+4 <16

x < 16

4

x<4

I hope this will help you

what is 98×63-32×69=

Answers

Answer: plz marl brainilist

3966

Step-by-step explanation:

(98 × 63 - 32 × 69

98 * 63) - (32 * 69)

Answer:

3966

Step-by-step explanation:

98 x 63 - 32 x 69 =

Multiply

6174 - 2208

Subtract

3966

The graph shows the solution of the following system of equations. y=-5/3x+3 y=1/3x-3 What is the solution? A. (-3,2) B. (3,2) C. (-3,-2) D. (3,-2)

Answers

Answer:

(3,-2)

Step-by-step explanation:

-5/3x + 3 = 1/3x - 3

-5/3x = 1/3x - 6

-2x = -6

x = 3

y = -5/3(3) + 3

y = -5 + 3

y = -2

Solve the inequality

Answers

Answer:

hope this helps buddy, please mark the brainliest.

Step-by-step explanation:

what is symmetrical line​

Answers

Answer:

assuming youre asking for line of symmetry, it's a line that cuts a shape exactly in half.  

for example, a square has 4 lines of symmetry

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