A telephone exchange operator assumes that 7% of the phone calls are wrong numbers. If the operator is accurate, what is the probability that the proportion of wrong numbers in a sample of 459 phone calls would differ from the population proportion by more than 3%

Answers

Answer 1

Answer:

0.0118 = 1.18% probability that the proportion of wrong numbers in a sample of 459 phone calls would differ from the population proportion by more than 3%

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

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]

A telephone exchange operator assumes that 7% of the phone calls are wrong numbers.

This means that [tex]p = 0.07[/tex]

Sample of 459 phone calls:

This means that [tex]n = 459[/tex]

Mean and standard deviation:

[tex]\mu = p = 0.07[/tex]

[tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\sqrt{\frac{0.07*0.93}{459}}} = 0.0119[/tex]

What is the probability that the proportion of wrong numbers in a sample of 459 phone calls would differ from the population proportion by more than 3%?

Proportion below 0.07 - 0.03 = 0.04 or above 0.07 + 0.03 = 0.1. Since the normal distribution is symmetric, these probabilities are the same, which means that we find one of them and multiply by 2.

Probability the proportion is below 0.04.

p-value of Z when X = 0.04. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{0.04 - 0.07}{0.0119}[/tex]

[tex]Z = -2.52[/tex]

[tex]Z = -2.52[/tex] has a p-value of 0.0059

2*0.0059 = 0.0118

0.0118 = 1.18% probability that the proportion of wrong numbers in a sample of 459 phone calls would differ from the population proportion by more than 3%


Related Questions

Find m a 24.7
b 79.2
c 68.3
d 57.4
e 46.5
f 80.1
g 35.6

Answers

Answer:

68.3 degrees

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

tan I = opp side / adj side

tan I = sqrt(82) / sqrt(13)

tan I = sqrt(82/13)

Taking the inverse tan of each side

tan ^-1 ( tan I) = tan ^-1( sqrt(82/13))

I = 68.2892

Rounding to the nearest tenth

I = 68.3 degrees

please help this is due right now

Answers

Answer:

108.82

Step-by-step explanation:

Evaluate the expression.
I-4|


PLEASE HELP BAHIAJSUEKSJN

Answers

Answer:

the answer is 4

Step-by-step explanation:

the answer will be positive

Karissa purchased a set of LED lights online that normally sells for $72.00 but was marked down to $48.96. What is the discount rate Karissa received? (2 points)
32%
47%
68%

Answers

47 % because it didn’t go down as much as the other ones would be

Make
x
the subject of the formula
x
+
4
=
q

Answers

Answer:

x = q-4

Step-by-step explanation:

x+4 = q

Subtract 4 from each side

x+4-4 = q-4

x = q-4

Answer:

x + 4

Step-by-step explanation:

x + 4 = q

4 = x + q

4 = x

x + 4

How to change unit from feet to cm

Answers

to change unit from feet to cm just divide the length value by 30.48......

Round to the nearest whole number.
6.4

Answers

Answer:

6

Step-by-step explanation:

Walnut High Schools Enrollment is exactly five times as large as the enrollment at walmut junior high the total enrollment for the two schools is 852 what is the enrollment at each school​

Answers

Answer:

142

Step-by-step explanation:

If the enrollment is five times as big, then that is six different things. So, take 852 and divide it by 6 to get 142. Or in other words:

852÷6=142

142x6=856

I hope this helps. Cheers^^

If b < 0 and a/b > c/b, then what is the relationship between a and c?

Answers

Answer:

a < c

Step-by-step explanation:

Given inequality:

a/b > c/b

Since b is negative, when multiplied by b, the inequality changes to opposite direction:

b(a/b) < b(c/b)a < c

A student majoring in accounting is trying to decide on the number of firms to which he should apply. Given his work experience and grades, he can expect to receive a job offer from 70% of the firms to which he applies. The student decides to apply to only four firms.
(a) What is the probability that he receives no job offer?
(b) How many job offers he expects to get?
(c) What is the probability that more than half of the firms he applied do not make him any offer?
(d) What assumptions do you need to make to find the probabilities? To increase the chance of securing more job offers, the student decides to apply to as many companies as possible, he sent out 60 applications to all different accounting firms.
(e) What is the probability of him securing more than 3 offers?

Answers

Answer:

a) 0.0081 = 0.81% probability that he receives no job offer

b) He expects to get 2.8 job offers.

c) 0.0837 = 8.37% probability that more than half of the firms he applied do not make him any offer.

d) Each job must be independent of other jobs. Additionaly, if [tex]np \geq 10[/tex] and [tex]n(1-p) \geq 10[/tex], the normal approximation to the binomial distribution can be used.

e) 0.2401 = 24.01% probability of him securing more than 3 offers.

Step-by-step explanation:

For each application, there are only two possible outcomes. Either he gets an offer, or he does not. The probability of getting an offer for a job is independent of any other job, 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.

He can expect to receive a job offer from 70% of the firms to which he applies.

This means that [tex]p = 0.7[/tex]

The student decides to apply to only four firms.

This means that [tex]n = 4[/tex]

(a) What is the probability that he receives no job offer?

This is [tex]P(X = 0)[/tex]. So

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

[tex]P(X = 0) = C_{4,0}.(0.7)^{0}.(0.3)^{4} = 0.0081[/tex]

0.0081 = 0.81% probability that he receives no job offer.

(b) How many job offers he expects to get?

The expected value of the binomial distribution is:

[tex]E(X) = np[/tex]

In this question:

[tex]E(X) = 4(0.7) = 2.8[/tex]

He expects to get 2.8 job offers.

(c) What is the probability that more than half of the firms he applied do not make him any offer?

Less than 2 offers, which is:

[tex]P(X < 2) = P(X = 0) + P(X = 1)[/tex]

So

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

[tex]P(X = 0) = C_{4,0}.(0.7)^{0}.(0.3)^{4} = 0.0081[/tex]

[tex]P(X = 1) = C_{4,1}.(0.7)^{1}.(0.3)^{3} = 0.0756[/tex]

Then

[tex]P(X < 2) = P(X = 0) + P(X = 1) = 0.0081 + 0.0756 = 0.0837[/tex]

0.0837 = 8.37% probability that more than half of the firms he applied do not make him any offer.

(d) What assumptions do you need to make to find the probabilities? To increase the chance of securing more job offers, the student decides to apply to as many companies as possible, he sent out 60 applications to all different accounting firms.

Each job must be independent of other jobs. Additionaly, if [tex]np \geq 10[/tex] and [tex]n(1-p) \geq 10[/tex], the normal approximation to the binomial distribution can be used.

(e) What is the probability of him securing more than 3 offers?

Between 4 and n, since n is 4, 4 offers, so:

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

[tex]P(X = 4) = C_{4,4}.(0.7)^{4}.(0.3)^{0} = 0.2401[/tex]

0.2401 = 24.01% probability of him securing more than 3 offers.

PLS HELP IM CONFUSED
Given the graph of a radical function, which statement is correct?

Radical function going from the point negative 3 comma negative 2 up to the right through the point comma 0

A. R colon open bracket y is an element of all real number close bracket
B. R colon open bracket y is an element of all real numbers such that y is greater than or equal to negative 3 close bracket
C. R colon open bracket y is an element of all real numbers such that y is greater than or equal to negative 2 close bracket
D. R colon open bracket y is an element of all real numbers such that y is greater than or equal to 1 close bracket

Answers

Answer:

The answer to your question will be the choice "D."

in how many ways 6 gentleman and 4 ladies can be choosen out of 10 gentleman and 8 ladies? ​

Answers

Answer:

5880 ways

Step-by-step explanation:

For selections like this, we solve using the combination theory. Recall that

nCr = n!/(n-r)!r!

Hence given to find the number of ways 6 gentleman and 4 ladies can be choosen out of 10 gentleman and 8 ladies,

= 10C6 * 8C4

= 10!/(10-6)!6! * 8!/(8-6)!6!

= 10 * 9 * 8 * 7 * 6!/4 *3 *2 * 6! * 8 * 7 * 6!/2 * 6!

= 210 * 28

= 5880 ways

The arrangement can be done in 5880 ways

Helpppp please !! Thank you :)

Answers

Answer: Because they are corresponding angles (second option is the answer).

Answer:

second option...because they are corresponding angles..

STEP BY STEP EXPLANATION: corresponding angles are formed when two parallel lines are intersected by the transversal

the corresponding angles are 2 and 6

I NEED HELP ON C,E,F,G PLEASE ASAP!!!!

Answers

Answer:
C. 364.4
E. 14
F. 21
G. 96°

Solve for x the find the measure of A

Answers

Answer:

84°

Step-by-step explanation:

the total angle in a straight line sum up to 180°

A coffee pot holds 3 3/4 quarts of coffee. How much is this in cups

Answers

Answer:

15 cups

Step-by-step explanation:

1 quart = 4 cups

3.75 quarts = (3.75 * 4) cups

3.75 quarts = 15 cups

3.75 quarts mean 15 cups

What is unitary method?

The unitary approach is a strategy for problem-solving that involves first determining the value of a single unit, then multiplying that value to determine the required value.

Given

1 quart = 4 cups

3.75 quarts = (3.75 * 4) cups

3.75 quarts = 15 cups

To know more about unitary methods refer to:

https://brainly.com/question/27989833

#SPJ2

What is the slope of the line that passes through the points (4, 10) and (1,10)?
Write
your answer in simplest form.

Answers

Answer:

0

Step-by-step explanation:

We have two points so we can use the sloe formula

m = (y2-y1)/(x2-x1)

   = ( 10-10)/(1-4)

  = 0/ -3

  = 0

Answer:

Slope is 0

explanation:

Slope is the same as gradient.

Formular:

[tex]{ \boxed{ \bf{slope = \frac{y _{2} - y _{1}}{x _{2} - x _{1} } }}}[/tex]

Substitute the variables:

[tex]{ \tt{slope = \frac{10 - 10}{1 - 4} }} \\ \\ = { \tt{ \frac{0}{ - 3} }} \\ = 0[/tex]

Solve the formula for the specific variable
Z=x-y/3
Y=____

Answers

Answer:

-3(z-x) = y

Step-by-step explanation:

Z=x-y/3

Solve for y

Subtract x from each side

z-x = x- y/3 -x

z-x = -y/3

Multiply each side by -3

-3(z-x) = -y/3 * -3

-3(z-x) = y

Factor the following expressions completely. Show and check all work on your own paper.
x^2+169

Factor the following expressions completely. Show and check all work on your own paper.
5x^2-50x+125

Factor the following expressions completely. Show and check all work on your own paper.
100x^2-25y2

Answers

Answer:

See the expressions and the answers below

Step-by-step explanation:

Given data

The first expression is given as

x^2+169 .-> we can not factorize the expression anymore

The second expression

5x^2-50x+125

5(x^2-10x+25)

The third expression

100x^2-25y2

25(4x^2-y^2)

Solve each equation for the given variable?

Answers

Answer:

1. x = 20     2. n = 50

Step-by-step explanation:

1/4x - 2 = 3

1/4x = 5

x = 20

2. 8 = 1/5n - 2

10 = 1/5n

n = 50

Answer:

Question 1

Original equation:

1/4x-2=3

Add 2 to both sides:

1/4x=5

Multiply both sides by 4/1:

x=20

Question 2

Original equation:

8=1/5n x 2

Divide both sides by 2

4 = 1/5n

Multiply both sides by 5/1

n=20

Let me know if this helps!

Find the length of the missing side

Answers

Answer:

Step-by-step explanation:

Side=AC=9[tex]\sqrt{2}[/tex]

Side AB= x

Hypotenuse =CB= y

Side AB = 9[tex]\sqrt{2}[/tex]

Hypotenuse CB = 36

Enter a formula in cell B10 to return the value of 35000 if the net profit after tax cell B9 is greater than or equal to 470000 or 100 if it is not

Answers

Answer:

I hope it help and I guess it is correct

A binomial probability experiment is conducted with the given parameters. Compute the probability of x successes in the n independent trials of the experiment.
n=12​, p=0.35​, x=2

Answers

Answer:

0.1088 or 10.88%

Step-by-step explanation:

q = 1 - 0.35 = 0.65

P(X=2) = 12C2 × (0.35)² × (0.65)¹

= 0.1088

Is segment AB tangent to circle O shown in the diagram, for AB = 8, OB = 3.75, and AO = 10.25. Explain your reasoning and show all work in your own words. (The figure is not drawn to scale.)

Answers

9514 1404 393

Answer:

  not tangent

Step-by-step explanation:

AB will be tangent to circle O if AB ⊥ BO. That can be tested by checking to see if AB, BO, and AO satisfy the Pythagorean theorem.

According to the Pythagorean theorem, the length of the hypotenuse of a right triangle with legs 3.75 and 8 will be ...

  hypotenuse = √(3.75² +8²) = √78.0625 ≈ 8.835

The length of AO is somewhat greater than that, so AB cannot be a tangent to the circle.

__

The angle ABO is obtuse.

Shaun is planting trees along his driveway, and he has 66 redwoods and 66 pine trees to plant in one row. What is the probability that he randomly plants the trees so that all 66 redwoods are next to each other and all 66 pine trees are next to each other

Answers

Answer:

0.0022 = 0.22% probability that he randomly plants the trees so that all 6 redwoods are next to each other and all 6 pine trees are next to each other.

Step-by-step explanation:

The trees are arranged, so the arrangements formula is used to solve this question. Also, a probability is the number of desired outcomes divided by the number of total outcomes.

Arrangements formula:

The number of possible arrangements of n elements is given by:

[tex]A_n = n![/tex]

Desired outcomes:

Two cases:

6 redwoods(6! ways) then the 6 pine trees(6! ways)

6 pine trees(6! ways) then the 6 redwoods(6! ways)

So

[tex]D = 2*6!*6![/tex]

Total outcomes:

12 trees, so:

[tex]D = 12![/tex]

What is the probability that he randomly plants the trees so that all 6 redwoods are next to each other and all 6 pine trees are next to each other?

[tex]p = \frac{D}{T} = \frac{2*6!*6!}{12!} = 0.0022[/tex]

0.0022 = 0.22% probability that he randomly plants the trees so that all 6 redwoods are next to each other and all 6 pine trees are next to each other.

what percent of 70 is 35

Answers

Answer:

50%

Step-by-step explanation:

35 is halve of 70 therefore it is 50%

hope it helps u...........

Most linear graphs are direct variation, unless they go through the origin.

True

False

Answers

False

A linear graph that is a direct variation is in the form y=kx, so it has a y-intercept at (0,0). This means it passes through the origin if it is a direct variation.

A.) Evaluate f(1)

B.) given: f(x) =1, find x

Answers

Answer:

f(1) = -2

f(x) =1 when x=0 or x=-2

Step-by-step explanation:

f(1) is the y value when x=1

f(1) = -2

f(x) = 1 means find the x value when y=1

when y =1, x =0 and -2

Help please ….. help

Answers

Answer:

Step-by-step explanation:

a) categorical

b) add all of the numbers and divide by how many numbers there were.

c) outliers means any that were far away from the rest of the data

d) not entirely, you can make an estimate based on it, but nat an exact answer.

help fast please

how far does light travel per second?

Answers

9514 1404 393

Answer:

  3×10^8 m/s

Step-by-step explanation:

The desired speed is ...

  [tex]\dfrac{\dfrac{9.45\times10^{15}\text{ m}}{\text{yr}}}{\dfrac{3.15\times10^7\text{ s}}{\text{yr}}}=\dfrac{9.45}{3.15}\times10^{15-7}\text{ m/s}=\boxed{3.00\times10^8\text{ m/s}}[/tex]

__

Your calculator can help you figure this out.

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