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

The following three shapes are based only on squares, semi circles, and quarter circles. Find the perimeter in the area of each shaded part

Answers

Answer: 46.26

Step-by-step explanation:

Since it is a square the sides are all the same, and since it’s a half circle, the dashed line is the diameter of the circle. To find the circumference on a circle, the equation is diameter times pi. 3.14 is commonly used for pi which is what I’m using 3.14, but of you are told to use a different number use that. 9*3.14 is 28.26. Since ther are exactly two half circles in the diameter, here’s no point in dividing by 2. The rest of the perimeter are just 2 sides of the square. So 9+9+28.26 is 46.26.

Express the confidence interval

Answers

The answer I p



Explain k
2/3:34;(5-6)

Consider a study conducted to determine the average protein intake among an adult population. Suppose that a confidence level of 85% is required with an interval about 10 units wide . If a preliminary data indicate a standard deviation of 20g . What sample of adults should be selected for the study?​

Answers

Answer:

With an ageing population, dietary approaches to promote health and independence later in life are needed. In part, this can be achieved by maintaining muscle mass and strength as people age. New evidence suggests that current dietary recommendations for protein intake may be insufficient to achieve this goal and that individuals might benefit by increasing their intake and frequency of consumption of high-quality protein. However, the environmental effects of increasing animal-protein production are a concern, and alternative, more sustainable protein sources should be considered. Protein is known to be more satiating than other macronutrients, and it is unclear whether diets high in plant proteins affect the appetite of older adults as they should be recommended for individuals at risk of malnutrition. The review considers the protein needs of an ageing population (>40 years old), sustainable protein sources, appetite-related implications of diets high in plant proteins, and related areas for future research.

Use order of operations to solve. PEMDAS
7 + 8(32-2)

Answers

Answer:

247

Step-by-step explanation:

7 + 8(32-2)

Parentheses first

7 + 8(30)

Then multiply

7+240

Then add

247

Answer:

247

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right

Step-by-step explanation:

Step 1: Define

Identify

7 + 8(32 - 2)

Step 2: Evaluate

(Parenthesis) Subtract:                                                                                     7 + 8(30)Multiply:                                                                                                             7 + 240Add:                                                                                                                   247

The value of square root of -9 is not -3 because

Answers

Answer:

The square root of -9 cannot be -3 because -3 squared or -3 times -3 equals 9 not -9.

Hope this helps!

write your answer in simplest radical form​

Answers

9514 1404 393

Answer:

  4√2

Step-by-step explanation:

In a 30°-60°-90° triangle, the ratio of side lengths is ...

  1 : √3 : 2

That is, the hypotenuse (c) is double the short side (2√2).

  c = 4√2

From a club of 18 people, in how many ways can a group of five members be selected to attend a conference?

Answers

Selection here means you’ll use combination and not permutation.
Total number of members=18
Numbers to be selected=5
Therefore=18C5=n!/(n-r)!r!
=18!/(18-5)!5!
=18!/13!5!
=18x17x16x15x14x13!/13!x5x4x3x2x1
The 13 factorials will cancel out which will give
= 18x17x16x15x14\ 5x4x3x2x1
=1,028,160/120
=8,568ways.

write your answer as an integer or as a decimal rounded to the nearest tenth​

Answers

Answer:Mark Brainliest please

Answer is 4.86 which is rounded to 5

Step-by-step explanation:

Cos 40 degree = VW/7

0.694 =VW/7

0.694 * 7 =VW

4.858 =VW

VW=4.86 is the answer

How do you find the area of a parallelogram?

.A = lw

.A = bh

.A = 1/2 bh

.A = 1/3 bh

Answers

Answer:

1/2 bh

Step-by-step explanation:

Step-by-step explanation:

parallelogram has base and height so area of parallelogram is

A= bh

Which of the following behaviors would best describe someone who is listening and paying attention? a) Leaning toward the speaker O b) Interrupting the speaker to share their opinion c) Avoiding eye contact d) Asking questions to make sure they understand what's being said

Answers

Answer:

D

Step-by-step explanation:

If you ask questions while their speaking it shows that you are paying attention to them. Avoiding eye contact could mean your thinking about something else or you aren't interested. Interrupting them is just being disrespectful. Leaning towards them doesn't really do anything other than you moving.

There are 165 children taking swimming lessons at the pool. If 10 children will be assigned to each instructor, how many instructors are needed?

Answers

17 but one will have only 5 children

Answer:

17 instructors

Step-by-step explanation:

If each instructor will get 10 children, we have to divided the total number of children taking swimming lessons by the number of children assigned to each instructor (10):

165/10 = 16.5

Unfortunately, we can't have 16 and a half instructors. Since 5 children are remaining, we can round up 16.5 to 17 and get 17 instructors. This implies that 16 instructors will teach 10 children (160 in total) and 1 instructor will teach 5 children (5 in total). 160+5 = 165 total children.

is the sequence 1/6, 1/2, 3/2,9/2 arithmetic, or geometric

Answers

Answer:

geometric

Step-by-step explanation:

Find the length of x

Answers

Answer:

32

Step-by-step explanation:

Let's assume that the triangles are similar.

[tex]\frac{16}{12} = \frac{24}{18} = \frac{x}{24}[/tex]

[tex]\frac{x}{24} = \frac{4}{3} => x = \frac{24}{3} * 4= 8 * 4 = 32[/tex]

what is the sign of x/y times 7y^3 when x<0 and y>0? A. Positive B. Negative C. Zero​

Answers

X <0 means x would be negative.

For x/y, a negative divided by a positive would give a negative answer.

A negative multiplied by a positive would result in a negative.

The answer would be B. Negative

1. Đường kính của một loại trục máy là một đại lượng ngẫu nhiên có phân phối chuẩn N (μ = 250mm, σ2 = 25mm2). Trục máy được gọi là hợp quy cách nếu đường kính từ 245mm đến 255mm. Cho máy sản xuất 100 trục. Tính xác suất để:
a. Có 50 trục hợp quy cách.
b. Có không quá 80 trục hợp quy cách

Answers

Answer:

cannot understand the language man

but please follow

Two cards are selected with replacement from a standard deck of 52 cards. Find the probability of selecting a heart and then selecting a diamond.

Answers

Answer: 50.2 is it  

Step-by-step explanation: thats easy

Probability helps us to know the chances of an event occurring. The probability of selecting a heart and then selecting a diamond is 144/2652.

What is Probability?

Probability helps us to know the chances of an event occurring.

[tex]\rm Probability=\dfrac{Desired\ Outcomes}{Total\ Number\ of\ outcomes\ possible}[/tex]

Given that Two cards are selected with replacement from a standard deck of 52 cards. Therefore, the probability of selecting a heart and then selecting a diamond is,

Probability = (12/52) × (12/51)

Probability = 144/2652

Hence, The probability of selecting a heart and then selecting a diamond is 144/2652.

Learn more about Probability:

https://brainly.com/question/795909

#SPJ2

properties of exponents. the answer is 1/2^12 i need help with the work

Answers

Step-by-step explanation:

Answer in attached image...

hope it helps

(2^-1 -2^-1 × 2^-4)^2

(1/2 - 1/2 × 1/2^4)^2

(1/2 - 1/2^5)^2

(1/2 - 1/32)^2

(16/32-1/32)^2

(15/32)^2

(15/2^5)^2

Must click thanks and mark brainliest

Three numbers form an arithmetic sequence whose
common difference is 3. If the first number is
increased by 1, the second increased by 6, and
the third increased by 19, the resulting three
numbers form a geometric sequence. Determine
the original three numbers.

Answers

Let x be the first number in the sequence. Then the first three numbers are

{x, x + 3, x + 6}

The next sentence says that the sequence

{x + 1, x + 9, x + 25}

is geometric, which means there is some fixed number r for which

x + 9 = r (x + 1)

x + 25 = r (x + 9)

Solve for r :

r = (x + 9)/(x + 1) = (x + 25)/(x + 9)

Solve for x :

(x + 9)² = (x + 25) (x + 1)

x ² + 18x + 81 = x ² + 26x + 25

8x = 56

x = 7

Then the three numbers are

{7, 10, 13}

2. What is the number 643,581 rounded off
to the thousands place?
(1) 640,000
(2) 643,000
(3) 643,600
(4) 644,000
(5) 644,600

Answers

Answer:

(4) 644,000

Step-by-step explanation:

643,581

The 3 is in the thousands place

We look at the hundreds place

5

It is 5 or greater so we round the thousands place up 1

644000

Answer:

(2) 643,000

Step-by-step explanation:

Since 3 is a lesser number than 5 the number would be rounded to 643,000

Help with 5b please . thank you.​

Answers

Answer:

See explanation

Step-by-step explanation:

We are given f(x)=ln(1+x)-x+(1/2)x^2.

We are first ask to differentiate this.

We will need chain rule for first term and power rule for all three terms.

f'(x)=(1+x)'/(1+x)-(1)+(1/2)×2x

f'(x)=(0+1)/(1+x)-(1)+x

f'(x)=1/(1+x)-(1)+x

We are then ask to prove if x is positive then f is positive.

I'm thinking they want us to use the derivative part in our answer.

Let's look at the critical numbers.

f' is undefined at x=-1 and it also makes f undefined.

Let's see if we can find when expression is 0.

1/(1+x)-(1)+x=0

Find common denominator:

1/(1+x)-(1+x)/(1+x)+x(1+x)/(1+x)=0

(1-1-x+x+x^2)/(1+x)=0

A fraction can only be zero when it's numerator is.

Simplify numerator equal 0:

x^2=0

This happens at x=0.

This means the expression,f, is increasing or decreasing after x=0. Let's found out what's happening there. f'(1)=1/(1+1)-(1)+1=1/2 which means after x=0, f is increasing since f'>0 after x=0.

So we should see increasing values of f when we up the value for x after 0.

Plugging in 0 gives: f(0)=ln(1+0)-0+(1/2)0^2=0.

So any value f, after this x=0, should be higher than 0 since f(0)=0 and f' told us f in increasing after x equals 0.

The midpoint of has coordinates of (4, -9). The endpoint A has coordinates (-3, -5). What are the coordinates of B?

Answers

9514 1404 393

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)

A particle is moving with the given data. Find the position of the particle.

a(t) = [tex]t^{2}[/tex] − 4t + 5, s(0) = 0, s(1) = 20

How do I find s(t)=?

Answers

Recall that

[tex]\dfrac{dv(t)}{dt} = a(t) \Rightarrow dv(t) = a(t)dt[/tex]

Integrating this expression, we get

[tex]\displaystyle v(t) = \int a(t)dt = \int(t^2 - 4t + 5)dt[/tex]

[tex]\:\:\:\:\:\:\:= \frac{1}{3}t^3 - 2t^2 + 5t + C_1[/tex]

Also, recall that

[tex]\dfrac{ds(t)}{dt} = v(t)[/tex] or

[tex]\displaystyle s(t) = \int v(t)dt = \int (\frac{1}{3}t^3 - 2t^2 + 5t + C_1)dt[/tex]

[tex]\:\:\:\:\:\:\:= \frac{1}{12}t^4 - \frac{2}{3}t^3 + \frac{5}{2}t^2 + C_1t + C_2[/tex]

Next step is to find [tex]C_1\:\text{and}\:C_2[/tex]. We know that at t = 0, s = 0, which gives us [tex]C_2 = 0[/tex]. At t = 1, s = 20, which gives us

[tex]s(1) = \frac{1}{12}(1)^4 - \frac{2}{3}(1)^3 + \frac{5}{2}(1)^2 + C_1(1)[/tex]

[tex]= \frac{1}{12} - \frac{2}{3} + \frac{5}{2} + C_1 = \frac{23}{12} + C_1 = 20[/tex]

or

[tex]C_1 = \dfrac{217}{12}[/tex]

Therefore, s(t) can be written as

[tex]s(t) = \frac{1}{12}t^4 - \frac{2}{3}t^3 + \frac{5}{2}t^2 + \frac{217}{12}t[/tex]

At the movie theatre, child admission is 56.00 and adult admission is $9.60. On Sunday, twice as many adult tickets as child tickets were sold, for a total sales
of $907.20. How many child tickets were sold that day?

Answers

Did you mean 56 for child admission or was that a misclick

Please Help!
Function: y=x^2+5x-7
Vertex: (___,___)
Solutions: (___,___) and (___,___)

* i thought the vertex was (-5/2,-53,4) but apparently i’m wrong since it keeps saying it* i need answers please

Answers

Answer:

Step-by-step explanation:

What is the vertex of the graph of this function
y= -(x+2) (x+4)

Answers

Answer:

y=-(x+2)(x+4)

y=-(x^2+4x+2x+8)

y=-(x^2+6x+8)

y=-(x^2+4x+2x+8)

Y=-x(x+4)+2(x+4)

y=-(x+2)(X+4)

So vertex is (2,4)

Assume that human body temperatures are normally distributed with a mean of 98.19 and a standard deviation of 0.61

Answers

Answer:

Ok I'm assuming that know what??

Step-by-step explanation:

I NEED HELP PLEASE !!!

Answers

Answer: Because [tex]\frac{\pi }{3} =\frac{180\°}{3} =60\°[/tex], therefore [tex]\frac{\pi }{3} =60\°[/tex].


[tex] - x ^{2} + 2x - 6 = 0[/tex]
how to do,I don't know the step

answer is
[tex]x = 1 - \sqrt{5} i \: \: \: \: \: or \: \: 1 + \sqrt{5} i[/tex]

Answers

Answer:

there are several methods to "solve a quadratic"

you can look them all up...

Graphing, factoring, completing the square, taking roots, quadratic formula are the common methods....

given the way you are asking the question I think that you are supposed to use the quadratic formula ..

please look at the image of the formula and

realize that you problem has

a=-1

b=2

c=6

just plug in those numbers into the formula and you will get the results in the "answer"

NOTE [tex]\sqrt{-x}[/tex] is written as ix ( [tex]\sqrt{-25} = 5i[/tex] )

Step-by-step explanation:

x= -2+√ (2)²- (4)(-1)(-6)  

                 (2)(-1)  

and

x= -2-√ (2)²- (4)(-1)(-6)  

             (2)(-1)  

Mr. Jerome has an outstanding balance of $12000 on his credit card. The interest rate on the card is 12% he intends to pay off
the card in 2 years. Find the APR on the card.

Answers

the answer is 56 cards
because you add both sides by the same number
The person above me is correct

equation of a line with slope -1 and y intercept 0,-2

Answers

Answer:

y = - x - 2

Step-by-step explanation:

y=mx+b

m refers to slope

b refers to y intercept

y = (-1)x + (-2)

y = - x - 2

Answer:

y=-1x-2

Step-by-step explanation:

plug in the slop and y intercept to the equation y=mx+b

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