The average telephone bill in a locality is $70, with a standard deviation of $40. In a sample of 50 randomly selected phone connections, what is the probability that the sample average will exceed $75?

Answers

Answer 1

Using the normal distribution, there is a 0.1894 = 18.94% probability that the sample average will exceed $75.

Normal Probability Distribution

The z-score of a measure X of a normally distributed variable with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex] is given by:

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

The z-score measures how many standard deviations the measure is above or below the mean. Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.By the Central Limit Theorem, the sampling distribution of sample means of size n has standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

The parameters for this problem are given as follows:

[tex]\mu = 70, \sigma = 40, n = 50, s = \frac{40}{\sqrt{50}} = 5.66[/tex]

The probability that the sample average will exceed $75 is one subtracted by the p-value of Z when X = 75, hence:

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

By the Central Limit Theorem

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

Z = (75 - 70)/5.66

Z = 0.88

Z = 0.88 has a p-value of 0.8106.

1 - 0.8106 = 0.1894.

0.1894 = 18.94% probability that the sample average will exceed $75.

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Related Questions

i need help quick, everything is in the image

Answers

Answer:

x = 3

Step-by-step explanation:

see image. Instead of distributive property, let's multiply by 2 to get rid of the fraction and also the parenthesis on the left. See image.

Then subtract 5 and finally, divide by 3 to solve. See image.

Distribute to create an equivalent expression with the fewest symbols possible.
7(4p + 2q + 3r) =7(4p+2q+3r)

Answers

The equivalent expression for the given expression is 28p + 14q + 21r.

What is an equivalent expression?

An expression that gives the same value as the original expression when the same value of a variable is substituted is said to be an equivalent expression.

An equivalent expression is simplified to the original expression by using the distributive property.

What is distributive property?

The distributive property is

a(b + c) = ab + ac

Calculation:

The given expression is 7(4p + 2q + 3r)

Applying the distributive property,

7(4p + 2q + 3r) = 7(4p) + 7(2q) + 7(3r)

⇒ 28p + 14q + 21r

Thus, the equivalent expression for the given expression is 28p + 14q + 21r.

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7(4p+2q+3r)=7(4p+2q+3r)

Apply distributive law

a(b+c)=ab+ac

So

28p+14q+21r=28p+14q+21r

This is the required expression

Let g be a one-to-one function and suppose f is the inverse function of g
if g(5)=11 and g(3)=5, find f(5)

Answers

Answer:

So g(6) comes out to be 2.

Step-by-step explanation:

So f(6)=5 means when f acts on 6, the result is 5....so the inverse would take 5 back to 6...or g(5)=6

So f(2)=6 means that f reassigns 2 to 6....so the inverse would take 6 back to 2....or g(6)=2

hope this helps :)

Answer: 3

Step-by-step explanation:

If f(x) = y, then invf(y) = x
So, f(5) = invg(5) = 3

Solve the inequality and enter your solution as an inequality comparing the
variable to a number.
x-30 > 30

Answers

Answer:

[tex]x > 60[/tex]

Step-by-step explanation:

[tex]x-30 > 30[/tex]
[tex]x > 60[/tex] (add 30 onto both sides of the inequality)

a swimming pool charges £3.60 for entry. you can save 1/3 of entry fee with a membership card. on his first visit, ken spends £5 on a membership card plus the reduced entry fee. how many times does ken visit before he gets back his £5

Answers

Answer:

5

Step-by-step explanation:

You save ⅓ of entry fee, so you save 1.20 and you pay 2.40. We only really care about the 1.20 reduction. 5 / 1.2 = 4.16 so he must go 5 times to get the 5 back

laura spends 4 hours reading a book that is 76 pages long. what is the average number of pages she read per hour?

Answers

The average number of pages she reads per hour is 19 pages per hour

How to determine the average number of pages she read per hour?

The given parameters are:

Number of pages = 76 pages

Number of hours = 4 hours

The average number of pages she reads per hour is calculated using the following formula

Average = Number of pages/Number of hours

Substitute the known values in the above equation

Average = 76 pages/4 hours

Evaluate the quotient

Average = 19 pages per hours

Hence, the average number of pages she reads per hour is 19 pages per hours

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Round 229.371to the nearest one tenth and hundredths

Answers

Answer:

229.37, 229.4

Step-by-step explanation:

1. Hundredths
2. Tenths

229.37 and 229.4
explanation:

How do you compute this? 4(-2, 3) - 2(6, -7)

Answers

Step-by-step explanation:

Factor out two from the expression. The answer should be 2(2*(-2, 3)-(6, -7))


lim
n->infinity 4n^3-5/9n^3+7

Answers

Answer:

[tex]\lim_{n\rightarrow +\infty } \frac{4n^{3}-5}{9n^{3}+7}=\frac{4}{9}[/tex]

Step-by-step explanation:

[tex]\lim_{n\rightarrow +\infty } \frac{4n^{3}-5}{9n^{3}+7}[/tex]

Pull out  n³

[tex]=\lim_{n\rightarrow +\infty } \frac{n^{3}\times \left( 4-\frac{5}{n^3} \right) }{n^{3}\times \left( 9+\frac{7}{n^3} \right) }[/tex]

Simplify by n³

[tex]=\lim_{n\rightarrow +\infty } \frac{ \left( 4-\frac{5}{n^3} \right) }{ \left( 9+\frac{7}{n^3} \right) }[/tex]

Remark : [tex]\lim_{n\rightarrow +\infty } \frac{5}{n^3} \right) } = 0 \ \. \text{and} \ \ \lim_{n\rightarrow +\infty } \frac{7}{n^3} \right) } = 0[/tex]

Then

[tex]\lim_{n\rightarrow +\infty } \frac{ \left( 4-\frac{5}{n^3} \right) }{ \left( 9+\frac{7}{n^3} \right) }=\frac{4-0}{9+0}[/tex]

[tex]=\frac{4}{9}[/tex]

A box contains 5 reams of paper. How could you estimate the thickness of 2 sheets of paper? One ream of paper is 500 sheets.

Please provide deep explanation so i can learn and understand

Answers

The estimated thickness of 2 sheets of paper, given the parameters, is 0.0216 cm.

What is the thickness of a sheet of paper?

The thickness of a sheet of paper can be measured using a screw gauge or vernier caliper.

If the thickness of a ream of paper, which contains 500 sheets, is given, a sheet will be x/500 thick.

The thickness of 2 sheets of paper will be the thickness of a sheet multiplied by 2.

Data and Calculations:

Number of reams of paper in a box = 5 reams

1 ream = 500 sheets

500 sheets = 5.4 cm thick

The thickness of 2 sheets of paper = 0.0216 cm {5.4cm x 2/500)}

Thus, the estimated thickness of 2 sheets of paper, given the parameters, is 0.0216 cm.

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Question Completion:

Assume that one ream of paper is 5.4 cm thick.

During a drought, the water level in a reservoir dropped 3 in. each week for 5 straight weeks. Express the overall change in water level as a signed number.​

Answers

Answer:

v = -3w

Step-by-step explanation:

water level/volume = -3 x weeks

v = -3w

Glynn's car has a 18 gallon gas tank. He travels 450 miles. What is the least miles per gallon this trip? Write and solve an inequality to answer the question.

Answers

The least miles per gallon this trip is 25 miles per gallon

How to determine the least miles per gallon?

The given parameters are:

Distance = 450 miles

Tank size = 18 gallons

The least miles per gallon this trip is calculated as:

Miles per gallon = Distance/Tank size

This gives

Miles per gallon = 450/18

Evaluate the quotient

Miles per gallon =25

Represent as an inequality

x >= 25

Hence, the least miles per gallon this trip is 25 miles per gallon

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If the measure of WZX is 262 what is the measure of XWY?

Answers

Answer:

49°

Step-by-step explanation:

The circumference of a circle measures 360 degrees, so arc XW is 98°.

So, angle XWY is 49°.

Ke'o went shopping and spent $114 on clothes
and bought 5 pocket squares for the same price and one pairs
of $14 shorts. Write an equation for this story
problem, then solve for the price of the shirts.
Select two answers.

A. equation: 5[x+(1)(14)] = 114

B. price of each pocket square: $28

C. price of each pocket square: $25

D.equation: [(1)(14) - 5] = 114

E. price of each pocket square: $20

F. price of each pocket square: $19

G. equation: [5+ (1)(14)] = 114

H. equation: 5x+(1)(14) = 114

Answers

Equation H and answer E are correct

5x + 14 = 114
5x = 100
x = 20

Please help 50 points

Answers

Answer:

m∠RQS = 109°

Step-by-step explanation:

Angles on a straight line sum to 180°.

Therefore:

⇒ m∠RQS + m∠SQT = 180°

⇒ (15x + 4) + (10x + 1) = 180

⇒ 15x + 4 + 10x + 1 = 180

⇒ 15x + 10x + 4 + 1 = 180

⇒ 25x + 5 = 180

⇒ 25x + 5 - 5 = 180 - 5

⇒ 25x = 175

⇒ 25x ÷ 25 = 175 ÷ 25

⇒ x = 7

Now that we have found the value of x, substitute this into the expression for m∠RQS:

⇒ m∠RQS = 15(7) + 4

                  = 105 + 4

                  = 109°

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Two jets leave an air base at the same time and travel in opposite directions. One jet travels 80 mi/h faster than the other. If the two jets are 11392 miles apart after 8 hours, what is the rate of each jet

Answers

The rate of the slower jet is 672 miles per hour.

The rate of the slower jet is 752 miles per hour.

How to find the rate of the jets?

Two jets leave an air base at the same time and travel in opposite directions.

One jet travels 80 mi/h faster than the other.

let

x = rate of the slower jet

faster jet = 80 + x

Therefore,

rate = distance / time

The two jets are 11392 miles apart.

(80 + x)8 + 8x = 11392

640 + 8x + 8x = 11392

640 + 16x = 11392

16x = 11392 - 640

16x = 10752

divide both sides by 16

x = 10752 / 16

x = 672 miles per hour

rate of the faster jet = 80 + 672 = 752 miles per hour

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PLEASE ASAP!! ALSO PLEASE INCLUDE AN EXPLANATION OF HOW YOU GOT THE ANSWER!!! THANK YOU! BTW THERE ARE TWO PICTURES! :)

Answers

2/3 is 400% of 1/6

0.2 is 12.5% of 1 3/5

Calculating Percentages

From the question, we are to determine what percent of 1/6 is 2/3

Let the value be x

Thus,

We can write that

2/3 is x% of 1/6

This means

2/3 = x/100 × 1/6

Now, solve for x

2/3 = x/100 × 1/6

2/3 = x/600

x = (2×600)/3

x = 400

Hence, 2/3 is 400% of 1/6

We are to determine what percent of 1 3/5 is 0.2

Let the value be y

That is,

0.2 is y% of 1 3/5

This can be written as

0.2 = y% × 1.6

0.2 = y/100 × 1.6

Now, solve for y

0.2 = y/100 × 1.6

0.2 = 1.6y/100

1.6y = 0.2 × 100

1.6y = 20

y = 20/1.6
y = 12.5

Hence, 0.2 is 12.5% of 1 3/5

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How many pairs of parallel faces does this shape have?

Answers

Answer: one

Step-by-step explanation:

parallel faces are the ones that are opposite to each other.

Answer:

one

Step-by-step explanation:

there is only one pair of parallel faces.

Time to use my tools

96 100 132
6 ... 4 ....6
5....7......3
21...32...?

1)32
2)20
3)25
4)30


find the missing one

Answers

Answer:

the correct answer is 25

The figure shows a cylinder of diameter 12cm and height = 15cm. A hole in the shape of cone is bored into one of its end. If the cone has diameter equal to half of the diameter of the cylinder. find the volume of the remaining solid.​

Answers

Answer:

[tex]\bold{495\pi} \approx \bold{1555.088 cm^3}[/tex]

Step-by-step explanation:

There was no figure but the question is clear

Volume of a cylinder is given by the formula [tex]\bold{\pi r^2h}\\[/tex]

where r is radius of base of cylinder, h is the height

Volume of a cone is given by [tex]\bold{\frac{1}{3} \pi r^2 h}[/tex]

where r is the radius of base of cone, h is the height

The radius of the cylinder = [tex]\frac{1}{2}[/tex](diameter) = [tex]\frac{1}{2}[/tex](12) = 6cm

Height of cylinder = 15cm

Volume of cylinder [tex]V_{cyl} = \pi (6)^2 15 = \pi (36)15 = \bold{540\pi}[/tex]

Radius of cone = [tex]\frac{1}{2}[/tex] (radius of cylinder) = [tex]\frac{1}{2}[/tex](6) = 3 cm

Height of cone same as height of cylinder = 15cm

Volume of cone, [tex]V_{cone} = \frac{1}{3}\pi r^2 h = \frac{1}{3}\pi (3)^2 15 = \frac{1}{3}(9)15\pi = \bold{45\pi}\\[/tex]


Difference is the volume of the remaining solid

[tex]V_{cyl} - V_{cone} = 540\pi - 45\pi = \bold{495\pi} \approx \bold{1555.088 cm^3}[/tex]



A home gardener estimates that 18 apple trees will produce an average yield of 80 apples per tree. But because of the size of the garden, for each additional tree planted, the yield will decrease by four apples per tree. How many trees should be planted to maximize the total

Answers

19 trees should be planted to maximize the total

How many trees should be planted to maximize the total

From the question, we have the following parameters:

Number of apples, x = 18

Yield, f(x) = 80 per tree

When the number of apple trees is increased (say by x).

We have:

Trees = 18 + x

The yield decreases by four apples per tree.

So, we have

Yield = 80 - 4x

So, the profit function is

P(x) = Apples * Yield

This gives

P(x) = (18 + x) *(80 - 4x)

Expand the bracket

P(x) = 1440 - 72x + 80x - 4x^2

Differentiate the function

P'(x) = 0 - 72 + 80 - 8x

Evaluate the like terms

P'(x) = 8 - 8x

Set P'(x) to 0

8 - 8x = 0

Divide through by 8

1 - x = 0

Solve for x

x = 1

Recall that:

Trees = 18 + x

So, we have

Trees = 18 + 1

Evaluate

Trees = 19

Hence, 19 trees should be planted to maximize the total

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A television is identified by the diagonal measurement of the screen. A television has a length of 57-inches and a height of 33 inches. What is the length of the diagonal of the television screen?

Answers

Answer: 65.86 inches

Step-by-step explanation:

Length of the hypotenuse (length of diagonal) :  a^2 + b^2 = c^2

The length (a)= 57

The height (b) =33

57^2= 3,249

33^3= 1,089

3,249 + 1,089 = c^2

4,338 = c^2

We next square root both sides to find c by itself (length of the diagonal)

[tex]\sqrt{4,338} = c[/tex]

c= 65.8634952...

You can then round to however many decimals are required.

To the hundreds place: 65.86 inches

5. Based on your data, what is the experimental probability that the family has two dogs or
two cats?

Answers

Answer:

2 dogs

Step-by-step explanation:

Drag the tiles to the correct boxes to complete the pairs. Not all tiles will be used.
Match each given function with the description of its graph.
y-intercept at (0, 2)
graph initially decreases slowly and then decreases rapidly
y-intercept at (0, 1)
graph initially decreases rapidly and then decreases slowly
y-intercept at (0, 1)
graph initially increases rapidly and then increases slowly
y-intercept at (0, 2)
graph initially decreases rapidly and then decreases slowly
y-intercept at (0, 1)
graph initially increases slowly and then increases rapidly
Y =
(4)*
y = 3²
y = 2(1) ²

Answers

The statements that applies are;

y-intercept at (0, 2), graph initially decreases rapidly and then decreases slowly.y-intercept at (0, 1), graph initially increases slowly and then increases rapidlyy-intercept at (0, 1) - graph initially decreases rapidly and then decreases slowly.What is the function about?

The property of power function is known to be peculiar to the field of math. A power function is known to be one that is made up of a variable base that tends to be raised to a fixed power.

Note that the function is one that is made up of a constant base that is often raised to a variable power.

Following the property of power function, we can be able to obtain the information above.

Therefore, The statements that applies are;

y-intercept at (0, 2), graph initially decreases rapidly and then decreases slowly.y-intercept at (0, 1), graph initially increases slowly and then increases rapidlyy-intercept at (0, 1) - graph initially decreases rapidly and then decreases slowly.

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3. What is a variable?
numbers that represent letters
a combination of letters and numbers
Oletters that represent numbers
O a operation between different letters

Answers

I think it’s letters that represent numbers

Solve for y. Simplify your answer as much as possible. 9/12=y/8

Answers

Answer:

6

Step-by-step explanation:

Solve for y:

[tex]y/8=9/12[/tex]

Multiply both sides by 8:

[tex]y=72/12[/tex]

Solve fraction

[tex]y=6[/tex]

A baker has 4 3/4 pounds of cookie dough. He uses 1/16 pound of dough for each cookie. How many cookies can he make? Simplify the answer.

Answers

This shows that 76 cookies will be made with the total pounds of cookies

Ratio and proportion

Fractions are written as a ratio of two integers. Given the following parameters

Total pounds of cookies made = 4 3/4 pounds

Total pounds of cookies made = 19/4 pounds

If he uses 1/16 pound of dough for each cookie, the total amount of cookies made is given;

Number of cookies = 19/4 ÷ 1/16

Number of cookies = 19/4 * 16/1

Number of cookies = 19 * 4

Number of cookies = 76

This shows that 76 cookies will be made with the total pounds of cookies

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A survey was conducted among the students at Elmwood High School. What are the individuals in this study?

the types of sports
the music groups
the clubs
the students

Answers

Based on the information provided, the individuals in this study are: D. the students.

What is a study?

A study can be defined as a strategic process or technique through which a scientist (researcher) observes and measures the effect of a risk factors, diagnostic test, or treatments on a particular population of interest.

What is a variable?

In Mathematics, a variable can be defined as the measurable conditions, events, characteristics, individuals, or behaviors that a scientist (researcher) can control or observe when performing a study.

Based on the information provided, the individuals in this study are the students and these include the following subclasses:

FreshmenSophomoresJuniorsSeniors

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The students are the individuals in this study and is therefore denoted as option D.

What is a Sample?

This refers to a group of people which are chosen or taken from a large population for measurement or surveys.

In this scenario, the study was conducted in a school with different types of students according to their grades such as freshman, sophomore etc. This therefore makes the individuals in the study to be students and is the most appropriate choice.

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PLS HELP plsssssssssssssss

Answers

Answer:

a. 33

Step-by-step explanation:

a straight line is 180° so

3x = 180 - 81

3x = 99

to find x divide by 3

x = 99/3

x = 33

Alice placed $1,900 in a savings account which earns 2.2% interest, compounded every year. How much will she have in the account after 5 years.

Answers

She will have $2118 in her account after five years

How to determine the amount in five years?

The given parameters about the compound interest are

Principal Amount, P = $1,900

Interest Rate, R = 2.2%

Time, t = 5

Compound interests are different from simple interest, and they are calculated using the following compound interest formula

CI = P(1 + R)^t - P

To calculate the amount, we have:

A = P + CI

So, the equation becomes

A = P + P(1 + R)^t - P

Evaluate the like terms

A = P(1 + R)^t

Substitute the known values in the above equation

A = 1900 * (1 + 2.2%)^5

Express 2.2% as decimal

A = 1900 * (1 + 0.022)^5

Evaluate the sum

A = 1900 * (1.022)^5

Evaluate the exponent

A = 1900 * 1.11495

Evaluate the product

A = 2118

Hence, she will have $2118 in her account after five years

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