Suppose a large telephone manufacturer has a problem with excessive customer complaints and consequent returns of the phones for repair or replacement. The manufacturer wants to estimate the magnitude of the problem in order to design a quality control program. How many telephones should be sampled and checked in order to estimate the proportion defective to within 9 percentage points with 89% confidence

Answers

Answer 1

Answer:

80 telephones should be sampled

Step-by-step explanation:

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]1-\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]1 - \frac{\alpha}{2}[/tex].

The margin of error is of:

[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

89% confidence level

So [tex]\alpha = 0.11[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.11}{2} = 0.945[/tex], so [tex]Z = 1.6[/tex].

How many telephones should be sampled and checked in order to estimate the proportion defective to within 9 percentage points with 89% confidence?

n telephones should be sampled, an n is found when M = 0.09. We have no estimate for the proportion, thus we use [tex]\pi = 0.5[/tex]

[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

[tex]0.09 = 1.6\sqrt{\frac{0.5*0.5}{n}}[/tex]

[tex]0.09\sqrt{n} = 1.6*0.5[/tex]

[tex]\sqrt{n} = \frac{1.6*0.5}{0.09}[/tex]

[tex](\sqrt{n})^2 = (\frac{1.6*0.5}{0.09})^2[/tex]

[tex]n = 79.01[/tex]

Rounding up(as 79 gives a margin of error slightly above the desired value).

80 telephones should be sampled


Related Questions

You are dealt one card from a 52-card deck.

a) Find the odds in favor of getting a red king.

b) Find the odds against getting a red king.

Answers

Answer:

(a)So, there are 2 kings in red- one of hearts and the other of diamonds. Therefore, the probability of selecting a red king from a deck of cards= 2/52 or 1/26.

(b) There are 6 red face cards in a 52-card deck (so 46 other cards). PROBABILITIES compare the number of favorable outcomes to the total number of possible outcomes: The PROBABILITY of getting a red face card is 6/52 = 3/26.

The odds in favor of getting a red king will be 1/26. And the odds against getting a red king will be 25/26.

What is probability?

Its basic premise is that something will almost certainly happen. The percentage of favorable events to the total number of occurrences.

You are dealt one card from a 52-card deck.

Total events = 52

The odds in favor of getting a red king will be

Favorable events = 2

Then the probability will be

P = 2/52

P = 1/26

The odds against getting a red king will be

q = 1 – P

q = 1 – 1/26

q = 25/26

More about the probability link is given below.

https://brainly.com/question/795909

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Choose the system of inequalities that best matches the graph below.

Answers

Answer:

"D" is the correct answer

Step-by-step explanation:

Let v=-9i+j and w=-i-6j find 8v-6w

Answers

Answer:

78i+52j

Step-by-step explanation:

8(9i+2j)-6(-i-6j)

72i+16j+6i+36j

=78i+52j

I need help with this.

Answers

Answer:

A and b Are in quadrant 2. F and D are in quadrant 1. F is in quadrant 3 and C is in quadrant 4

Step-by-step explanation:

each quadrant is in the boxes and the question is asking what is each  coordinate is in what quadrant

HELP HELP HELP MATH⚠️⚠️⚠️⚠️⚠️

Find four consecutive integers with the sum of 2021

Answers

Answer:

This problem has not solution

Step-by-step explanation:

lets the  integers be:

x

x+1

x+2

x+3

so:

x+(x+1)+(x+2)+(x+3)=2021

x+x+x+x+1+2+3=2021

4x+6=2021

4x=2021-6=2015

x=2015/4=503.75

x is not a integer

ab=6cm ac=12 calculate the length of cd

Answers

Answer:

is that the full question?

Answer:

Solution:-

Given,

ab =perpendicular (p)= 6cm

ac =hypotenuse (h)= 12cm

cd =base (b)= ?

using , Pythagoras theorem we have ,

b²=√h²-p²

or,cd²=√ac²-ab²

= √12²-6²

= √144-36

=√108

=√10.8²

=10.8cm

the length of cd is 10.8 cm

hope it is helpful to you

By converting to an exponential expression, solve log2 (x + 5) = 4

Answers

Step-by-step explanation:

just insert a base of two at on both sides and solve.

The solution of the logarithmic equation ㏒ (x + 5) / ㏒ 2 = 4 will be 11.

What is the solution to the equation?

The allocation of weights to the important variables that produce the calculation's optimum is referred to as a direct consequence.

The logarithmic equation is given below.

㏒₂(x + 5) = 4

Simplify the equation, then we have

㏒ (x + 5) / ㏒ 2 = 4

㏒ (x + 5) = 4 × ㏒ 2

㏒ (x + 5) = ㏒ 2⁴

Take antilog on both sides, then we have

(x + 5) = 2⁴

(x + 5) = 16

x = 11

The solution of the logarithmic equation ㏒ (x + 5) / ㏒ 2 = 4 will be 11.

More about the solution of the equation link is given below.

https://brainly.com/question/545403

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Which of the following is a like radical to cube rt of 7x

Answers

Answer:

[tex]\sqrt[3]{7x}[/tex]

Step-by-step explanation:

Given

[tex]7x[/tex]

Required

The radical statement

Cube root is represented as:

[tex]\sqrt[3]{}[/tex]

Considering [tex]7x[/tex], the expression is:

[tex]\sqrt[3]{7x}[/tex]


A driver must decide whether to buy a new car for $24,000 or lease the same car over a four-year period. Under the terms of the lease, she can make a down payment
of $3000 and have monthly payments of $150. At the end of the four years, the leased car has a residual value (the amount she pays if she chooses to buy the car at
the end of the lease period) of $11,000. Assume she can sell the new car at the end of the four years at the same residual value. Is it less expensive to buy or
to lease?

Answers

Answer:

3000 is the answer this question.

Which of the following numbers is rational? Assume that the decimal patterns continue.

Answers

Answer:

[tex]\sqrt{49}[/tex]

Step-by-step explanation:

Define a rational number by a number able to expressed a fraction where the denominator is not 0 or 1.

Non-terminating (never-ending) decimals cannot be expressed as a fraction and therefore are irrational. However, recall that [tex]\sqrt{49}=7[/tex], which can be expressed as a fraction (e.g. [tex]\frac{14}{2}[/tex], etc). Thus, the answer is [tex]\boxed{\sqrt{49}}[/tex].

An automatic machine inserts mixed vegetables into a plastic bag. Past experience revealed that some packages were underweight and some were overweight, but most of them had satisfactory weight.
Weight % of Total Underweight 2.5 Satisfactory 90.0 Overweight 7.5a) What is the probability of selecting and finding that all three bags are overweight?b) What is the probability of selecting and finding that all three bags are satisfactory?

Answers

Answer:

a) 0.000016 = 0.0016% probability of selecting and finding that all three bags are overweight.

b) 0.729 = 72.9% probability of selecting and finding that all three bags are satisfactory

Step-by-step explanation:

The condition of the bags in the sample is independent of the other bags, which means that the binomial probability distribution is used 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.

a) What is the probability of selecting and finding that all three bags are overweight?

2.5% are overweight, which means that [tex]p = 0.025[/tex]

3 bags means that [tex]n = 3[/tex]

This probability is P(X = 3). So

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 3) = C_{3,3}.(0.025)^{3}.(0.975)^{0} = 0.000016[/tex]

0.000016 = 0.0016% probability of selecting and finding that all three bags are overweight.

b) What is the probability of selecting and finding that all three bags are satisfactory?

90% are satisfactory, which means that [tex]p = 0.9[/tex]

3 bags means that [tex]n = 3[/tex]

This probability is P(X = 3). So

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 3) = C_{3,3}.(0.9)^{3}.(0.1)^{0} = 0.729[/tex]

0.729 = 72.9% probability of selecting and finding that all three bags are satisfactory

What is the volume of a cone with a height of 27 cm
and a radius of 13 cm? Round your answer to the
nearest tenth.
Use the button on your calculator to complete this
problem.
V=
cm3

Answers

Answer:4778.3 cm^3

Step-by-step explanation: The formula for volume of a cone is V=1/3h pi r^2. By plugging in the height and the radius we get our answer.

Answer:

4778.4 :)

Step-by-step explanation:

Solve using the substitution method
16x – 4y = 16
4x - 4 = y​

Answers

Answer:

y = 4 x − 4

Step-by-step explanation:

i need help solving this .

Answers

Answer:b

Step-by-step explanation:

Answer:

just be smart trust me u dont need us to give u the answer ur super smart

Step-by-step explanation:

make me brainliest to help people be encourage

What is the coefficient of x2 in the expansion of (x + 2)??
O A.
2
OB.
3
O C.
4
OD.
6

Answers

x+2 in expansion of (x+2) ?

A

What is y=-2(x+3)^2+2

Answers

Answer:

y = -2(x + 3)² + 2

y = 2{ -(x + 3)²+ 1}

y = 2{ -(x² + 6x + 9) + 1}

y = 2{ -x² - 6x - 9 + 1}

y = 2{ -x² - 6x - 8 }

y = -2 { x² + 6x + 8}

OR

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

On Monday, 27 adults visited an amusement park. On Tuesday, 23 adults visited the amusement park. The enterance fee for the adults is Rs. 100. How much amount is collected from the adults in these two days?

PLEASE TELL FULL SOLUTION. ​

Answers

Answer:

5000

Step-by-step explanation:

Add the number of adults first: 27+23=50

Then multiply the number of adults by 100 for the fee.

50*100 = 5000

Answer:

within the two days a total of 5000$ where collected in the two days

Solution:

R= 100 per adult

1 adult = 100

27(R)+ 23(R) = 27(100)+ 23(100)

27(100)+23(100) =5000

or add both 27 and 23 and multiple by 100

50•100 = 5000

Can someone solve this for me and a couple more questions ?

Answers

Answer:

C. -4

Step-by-step explanation:

Answer:

(c) - 4

is your right answer

HELP ASAP! I don’t know how to solve this problem nor where to start. Can someone please help me out here?

Answers

Answer:   344

===============================================

Explanation:

It might help to draw out the picture as shown below. The pool itself (just the water only) is the inner rectangle. The outer rectangle is the pool plus the border of those 1 by 1 tiles.

The pool is a rectangle 90 feet by 80 feet. If we add on the tiles, then we get a larger rectangle that is 90+2 = 92 feet by 80+2 = 82 feet.

We add on 2 since we're adding two copies of "1" on either side of each dimension.

The larger rectangle's area is 92*82 = 7544 square feet

The smaller rectangle's area is 90*80 = 7200 square feet

The difference in areas is 7544-7200 = 344 square feet.

Each 1 by 1 tile is of area 1*1 = 1 sq foot, meaning that 344 tiles will get us the 344 square foot border around the pool.

For a particular species of wolf, 55% are female, 20% hunt in medium-sized packs, and 15% are both female and hunt in medium-sized packs. What is the percent of wolves that are female but do not hunt in medium-sized packs?

Answers

20% is the answer
55%-20%-15%=20%

The radius of a sphere is increasing at a rate of 2 mm/s. How fast is the volume increasing (in mm3/s) when the diameter is 60 mm?

Answers

Answer:

22608 mm³/s

Step-by-step explanation:

Applying chain rule,

dV/dt = (dV/dr)(dr/dt)............... Equation 1

Where dV/dr = rate at which the volume is increasing

But,

V = 4πr³/3

Therefore,

dV/dr = 4πr²............... Equation 2

Substitute equation 2 into equation 1

dV/dt = 4πr²(dr/dt).............. Equation 3

From the question,

Given: dr/dt = 2 mm/s, r = 60/2 = 30 mm

Consatant: π = 3.14

Substitute these values into equation 3

dV/dt = 4×3.14×30²×2

dV/dt = 22608 mm³/s

How would I draw the reflection over the line y=2x+5?

Answers

Answer:

Step-by-step explanation:

Need help with this really fast

Answers

Answer:

6

Step-by-step explanation:

You can apply the proportion of 9/6 to 4 to get 6:

6*(9/6)= 9

So

4*(9/6) = Length LA

6= Length LA

Answer:

Option C, or [tex]2\frac{2}{3}[/tex]

Explanation:

We can see that the Line FM in the smaller triangle dialates to Line LK in the bigger triangle by the scale factor of:

FM/LK

6/9 or 2/3

So we would know that to find out the value of LA in the bigger triangle we would have to dialate it’s corresponding side FI in the smaller triangle by the same scale factor:

4 * 2/3

=> [tex]2\frac{2}{3}[/tex] = LA

Hope this helps!

sets A and B have 3 and 6 elements respectively. what can be the minimum number of elements in AUB

Answers

Answer:

6

Step-by-step explanation:

n(AUB) = n(A) + n(B) - n(AnB)

n(AUB) can have the minimum number of elements if n(AnB) has the maximum number of elements.

n(AnB) maximum = 3

so n(AUB) = 3+6-3 = 6

Probabilityyyyyyyyyyyyyyy

Answers

Answer:

Reduce if needed, asked or necessary

Step-by-step explanation:

1. 4/10

2. 2/6

3. 4/10

4. more likely

Answer:

Since Probability Is Usually Written In Fraction Form OR Ratios

(Although It Really Doesn't Matter):

1.  4/10 (2/5)

2.  2/6  (1/3)

3.  6/10 (3/5)

(All Fraction Form)

Last Question:

I can't really see the bottom but probably its 'More likely' since you can already see a bunch of red marbles.

Step-by-step explanation:

This is the basic fraction form :  ____ / ____

Based on what they ask, like the probability of picking out a black marble, count the number of black marbles in the particular bag and put that number as the numerator. The denominator is the total amount of marbles in that particular bag. Hope this helps!

Simplify. v80

A. 16v5
B. 5v4
C. 4v5
D. 20v4

Answers

Hi!

√80 = √(16 • 5) = √(4² • 5) = 45

Assume that there is a 8​% rate of disk drive failure in a year. a. If all your computer data is stored on a hard disk drive with a copy stored on a second hard disk​ drive, what is the probability that during a​ year, you can avoid catastrophe with at least one working​ drive?

Answers

Answer:

0.9936 = 99.36% probability that during a​ year, you can avoid catastrophe with at least one working​ drive

Step-by-step explanation:

For each disk, there are only two possible outcomes. Either it works, or it does not. The probability of a disk working is independent of any other disk, which means that the binomial probability distribution is used 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.

Assume that there is a 8​% rate of disk drive failure in a year.

So 100 - 8 = 92% probability of working, which means that [tex]p = 0.92[/tex]

Two disks are used:

This means that [tex]n = 2[/tex]

What is the probability that during a​ year, you can avoid catastrophe with at least one working​ drive?

This is:

[tex]P(X \geq 1) = 1 - P(X = 0)[/tex]

In which

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 0) = C_{2,0}.(0.92)^{0}.(0.08)^{2} = 0.0064[/tex]

[tex]P(X \geq 1) = 1 - P(X = 0) = 1 - 0.0064 = 0.9936[/tex]

0.9936 = 99.36% probability that during a​ year, you can avoid catastrophe with at least one working​ drive

Consider the quadratic function y = 0.3 (x-4)2 - 2.5
Determine the axis of symmetry, x =

Answers

Answer:

[tex]x=4[/tex]

Step-by-step explanation:

We have the quadratic function:

[tex]\displaystyle y=0.3(x-4)^2-2.5[/tex]

And we want to determine its axis of symmetry.

Notice that this is in vertex form:

[tex]y=a(x-h)^2+k[/tex]

Where (h, k) is the vertex of the parabola.

From our function, we can see that h = 4 and k = -2.5. Hence, our vertex is the point (4, -2.5).

The axis of symmetry is equivalent to the x-coordinate of the vertex.

The x-coordinate of the vertex is 4.

Therefore, the axis of symmetry is x = 4.

1. Find the exact value of sin( a−B), given that sin a=−4/5 and cos B=12/13, with a in quadrant III and B in quadrant IV.

2. Find all real numbers in the interval [0,2pi) that satisfy the equation.

3sec^2 x tan x =4tan x

3. Simplify the following trigonometric expressions, using identities as needed:

sin(x)/1−cos(x) + 1−cos(x)/sin(x)

Answers

(1) Recall that

sin(x - y) = sin(x) cos(y) - cos(x) sin(y)

sin²(x) + cos²(x) = 1

Given that α lies in the third quadrant, and β lies in the fourth quadrant, we expect to have

• sin(α) < 0 and cos(α) < 0

• sin(β) < 0 and cos(β) > 0

Solve for cos(α) and sin(β) :

cos(α) = -√(1 - sin²(α)) = -3/5

sin(β) = -√(1 - cos²(β)) = -5/13

Then

sin(α - β) = sin(α) cos(β) - cos(α) sin(β) =  (-4/5) (12/13) - (-3/5) (-5/13)

==>   sin(α - β) = -63/65

(2) In the second identity listed above, multiplying through both sides by 1/cos²(x) gives another identity,

sin²(x)/cos²(x) + cos²(x)/cos²(x) = 1/cos²(x)

==>   tan²(x) + 1 = sec²(x)

Rewrite the equation as

3 sec²(x) tan(x) = 4 tan(x)

3 (tan²(x) + 1) tan(x) = 4 tan(x)

3 tan³(x) + 3 tan(x) = 4 tan(x)

3 tan³(x) - tan(x) = 0

tan(x) (3 tan²(x) - 1) = 0

Solve for x :

tan(x) = 0   or   3 tan²(x) - 1 = 0

tan(x) = 0   or   tan²(x) = 1/3

tan(x) = 0   or   tan(x) = ±√(1/3)

x = arctan(0) +   or   x = arctan(1/√3) +   or   x = arctan(-1/√3) +

x =   or   x = π/6 +   or   x = -π/6 +

where n is any integer. In the interval [0, 2π), we get the solutions

x = 0, π/6, 5π/6, π, 7π/6, 11π/6

(3) You only need to rewrite the first term:

[tex]\dfrac{\sin(x)}{1-\cos(x)} \times \dfrac{1+\cos(x)}{1+\cos(x)} = \dfrac{\sin(x)(1+\cos(x))}{1-\cos^2(x)} = \dfrac{\sin(x)(1+\cos(x)}{\sin^2(x)} = \dfrac{1+\cos(x)}{\sin(x)}[/tex]

Then

[tex]\dfrac{\sin(x)}{1-\cos(x)}+\dfrac{1-\cos(x)}{\sin(x)} = \dfrac{1+\cos(x)+1-\cos(x)}{\sin(x)}=\dfrac2{\sin(x)}[/tex]

In an examination every student took history or geography or both of 500 candidates 60% took history whiles 72% took geography. How many students took both subjects

Answers

Answer:

80 students

Step-by-step explanation:

Answer:

80

Step-by-step explanation:

60% of 500 = 300

72% of 500 = 360

40% of 500 = 200

28% of 500 = 140

300+360 = 660

660 - 2x = 500

660 - 500 = 2x

160 = 2x

2x = 160

x = 80

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