Show all your work. Indicate clearly the methods you use, because you will be scored on the correctness of your methods as well as on the accuracy and completeness of your results and explanations. The distribution of pH levels for all community swimming pools in a large county is approximately normal with mean 7.5 and standard deviation 0.2. According to swimming pool studies, the safest pH levels for water in swimming pools are between 7.2 and 7.8. (a) One community swimming pool in the county will be selected at random. What is the probability that the selected pool has a pH level that is not considered safe

Answers

Answer 1

Answer:

The  value is  [tex]P(A) =  0.133617[/tex]

Step-by-step explanation:

From the question we are told that

  The  mean is  [tex]\mu =  7.5[/tex]

  The standard deviation is  [tex]\sigma  =  0.2[/tex]

  The safest water level is  between  7.2 and  7.8

Generally the probability that the selected pool has a pH level that is not considered safe is mathematically represented as

       [tex]P(A) =  1 - P(7.2 \le X  \le 7.8 )[/tex]

Here  

      [tex]P(7.2 < X  < 7.8 ) = P(\frac{ 7.2 - \mu }{\sigma } <  \frac{X - \mu }{ \sigma } <\frac{ 7.8 - \mu }{\sigma }   )[/tex]

Generally [tex]\frac{X - \mu }{ \sigma } =  Z (The  \ standardized \  value  \  of  X )[/tex]

So

 [tex]P(7.2 < X  < 7.8 ) = P(\frac{ 7.2 - 7.5 }{0.2 } < Z <\frac{ 7.8 - 7.5 }{0.2 }   )[/tex]    

 [tex]P(7.2 < X  < 7.8 ) = P(-1.5 < Z <1.5)[/tex]  

=>  [tex]P(7.2 < X  < 7.8 ) = P(Z <  1.5) - P(  Z < - 1.5) [/tex]

From the z-table the probability of  (Z <  -1.5) and   (  Z <1.5)  are

    [tex]P(Z <  1.5) =  0.93319[/tex]

and  

    [tex]P(Z <  -1.5) =  0.066807[/tex]

So

      [tex]P(7.2 < X  < 7.8 ) =0.93319 - 0.066807 [/tex]

       [tex]P(7.2 < X  < 7.8 ) =0.0866383[/tex]

So

   [tex]P(A) =  1 - 0.0866383[/tex]

=>  [tex]P(A) =  0.133617[/tex]

Answer 2

The probability that the selected pool has a pH level that is not considered safe pool is 0.1336

The given parameters are:

[tex]\mathbf{\mu = 7.5}[/tex]

[tex]\mathbf{\sigma = 0.2}[/tex]

Start by calculating the probability that a pool is safe.

This is represented as: P(7.2 < x < 7.8)

Calculate the z-scores for x =7.2 and 7.8 using:

[tex]\mathbf{z = \frac{x - \mu}{\sigma}}[/tex]

So, we have:

[tex]\mathbf{z = \frac{7.2 - 7.5}{0.2} = -1.5}[/tex]

[tex]\mathbf{z = \frac{7.8 - 7.5}{0.2} = 1.5}[/tex]

So, we have:

[tex]\mathbf{P(7.2 < x < 7.8) = P(-1.5 < z < 1.5)}[/tex]

This gives

[tex]\mathbf{P(7.2 < x < 7.8) = P(z < 1.5) - P(z < -1.5)}[/tex]

Using z table of probabilities, we have:

[tex]\mathbf{P(7.2 < x < 7.8) =0.9332 - 0.0668}[/tex]

[tex]\mathbf{P(7.2 < x < 7.8) =0.8664}[/tex]

The probability that the pool is not safe is calculated using the following complement formula

[tex]\mathbf{P(Not\ Safe) = 1 - P(Safe)}[/tex]

So, we have:

[tex]\mathbf{P(Not\ Safe) = 1 -0.8664}[/tex]

[tex]\mathbf{P(Not\ Safe) = 0.1336}[/tex]

Hence, the probability that the pool is not safe is 0.1336

Read more about probabilities at:

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Related Questions

if caramel is put onto a sphere-shaped apple such that the surface area increase at a rate of 10 cm2/min, find the rate at which the diameter increases when the diameter is 15cm

Answers

Answer:

The diameter will increase at a rate of 1/30π cm/min

Step-by-step explanation:

Here we want to calculate the rate at which the diameter will increase

Mathematically, the area of a sphere is given as;

A = 4πr^2

But r = d/2

so A = 4 * π * d/2 * d/2 = πd^2

dA/d(d) = 2πd

Thus dd/dA = 1/2πd = 1/2 * π * 15 = 1/30π

Given dA/dt = 10

Mathematically;

d(d)/dt = d(d)/dA * dA/dt

dd/dt = 1/30π * 10 = 10/30π = 1/3π cm/min

Factor out the coefficient of the variable term. The expression 1/7a + 1/7 factored is___

Answers

Answer:

17 and [a+1] is the factor

Step-by-step explanation:

Given:

1/7a + 1/7

Find:

Factor

Computation:

1/7a + 1/7

By taking 1/7 as a common

1/7[a+1]

So,

17 and [a+1] is the factor

The coefficient of the variable term in factored form is; 1

The given expression is;

(1/7)a + 1/7

Now, we want to factorize this and this means that we will bring out the common factor of both terms.

The common factor of both terms is 1/7. Thus, we have;

(1/7)(a + 1)

The variable term is a and as such we see that it's coefficient inside the bracket is 1.

Read more at; https://brainly.com/question/2764126

if you subtract 19 from my number and multiply the difference by -2​, the result is -8

Answers

Answer:cool

Step-by-step explanation:

Answer:

23

Step-by-step explanation:

let the number be 'a'

-2(a - 19)= -8

open the brackets

-2a + 38 = -8

collect like terms

38 + 8 = 2a

46 = 2a

a = 23

Evaluate 12x−3y when x=−14 and y=3.

Answers

Answer:

-177

Step-by-step explanation:

12(-14) -3(3)

-168-9

-177

Answer:

-177

Step-by-step explanation:

Plug in -14 for x and 3 for y:

12(-14) - 3(3)

Note that when you multiply a positive and a negative number, your answer will be negative.

Multiply:

12 * -14 = -168

-3 * 3 = -9

Combine the terms:

-168 + (-9) = -168 - 9 = -177

-177 is your answer.

~

A backpack costs $18 and has a 7 percent tax. How much will Sheila have to pay for the backpack after tax?
O $1.26
O $5.40
O $19.26
O $30.60

Answers

Answer:

1

Step-by-step explanation:

1.26

19.26. Do not forget to add your backpacks cost to the tax. You can take 18 dollars times 1.07 to get the tax and add the tax to the 18. Hope that helps!

Pls help for Algebra 11b = 143

Answers

Answer:

b = 13

Step-by-step explanation:

Divide 143 by 11

So you need to move the number from left side to right side and device
B=143/11
=13

1.-Responde la pregunta: ¿para qué
me sirve el teorema de Pitágoras en la.
vida cotidiana?​

Answers

Answer:

Respuesta. Respuesta: El Teorema de Pitágoras sirve para resolver una multitud de problemas; por ejemplo de, cálculo de distancias en el plano, en los mapas, en la realidad. ... En general, el Teorema de Pitágoras se puede utilizar para hallar longitudes en donde intervienen triángulos rectángulos.

Last year, 450 people attended the Booster Club Breakfast. This year the number of people attending increased by 6%. Find the number of people who attended the breakfast this year.

Answers

Answer:

I'm pretty sure it's 477

Step-by-step explanation:

PLEASE QUICK BRAINLISET

Answers

Answer: the answer is f

Answer:

F

Step-by-step explanation:

the measure of angle one must be equal to the measure of angle five and when doing the math I got x=34 plug that into the equation for angle five i got 48 and the same for plugging it into the equation for angle one.

HELP FAST. I NEED THIS ANSWER FAST

Answers

Answer:

abunda la caca

( its 10m*9y)

Step-by-step explanation:

Answer:

First find the cubes and squares of the 1st and 2nd expression.

1st expression ⇒ [tex](-\frac{2}{3} x^2y)^3 = -\frac{8}{27}x^6y^3[/tex]

2nd expression ⇒ [tex](-\frac{3}{4}xy^2)^2 = -\frac{9}{16}xy^4[/tex]

Now you all you need to do is multiply the 1st expression to 2nd expression.

[tex]-\frac{8}{27}x^6y^3*-\frac{9}{16}xy^4\\\\= \frac{72}{432} x^7y^7[/tex]

what is 3,108 rounded to the nearest thousand

Answers

Answer:

3100

Step-by-step explanation:

Answer:

3,000

Step-by-step explanation:

If the question was about 3,500 it would be rounded to 4,000

If the question was about 2,499 it would be rounded to 2,000

If it is in between 3,449 and 2,500 then it would be rounded to 3,000 which 3,108 is

compare the price per dozen eggs at the local grocery store and at the supermarket Edward bought 8 dozen eggs in the supermarket how much did he save by buying eggs at the supermarket instead of the local store​

Answers

Answer:

8

Step-by-step explanation:

i'm a 12 year old girl and i get it  so you have to think about the local store  would be half witch would be 4 so the answer is 8

In the accompanying diagram, line a intersects line b.

Answers

Answer:

C. 10

Step-by-step explanation:

[tex] (x + 5) = (2x - 5) [/tex] (vertical angles are congruent)

[tex] x + 5 = 2x - 5 [/tex]

Add 5 to both sides

[tex] x + 5 + 5 = 2x [/tex]

[tex] x + 10 = 2x [/tex]

Subtract x from both sides

[tex] 10 = 2x - x [/tex]

[tex] 10 = x [/tex]

[tex] x = 10 [/tex]

17. The hourly temperature at Portland, Oregon, on a particular day is recorded below.

1 A.M. 2 3 4 5 6 7 8 9 10 11 12 Noon
46° 44° 43° 41° 40° 40° 41° 43° 46° 52° 65° 69°
1 P.M. 2 3 4 5 6 7 8 9 10 11 12 Midnight
72° 74° 75° 75° 77° 75° 74° 70° 62° 55° 51° 48°

a. Find the amplitude of a sinusoidal function that models this temperature variation.
b. Find the vertical shift of a sinusoidal function that models this temperature variation.
c. What is the period of a sinusoidal function that models this temperature variation?
d. Use t = 0 at 5 P.M. to write a sinusoidal function that models this temp. variation.
e. What is the model’s temperature at 10 A.M.? Compare this to the actual value?

Answers

Answer:

a. Amplitude: 19.65446

b. Vertical Shift: 58.00713

c. Period: 2/0.22797 = 27.56146

d. 19.65446 * sin(0.22797x + 1.79552) + 58.00713

e. Model's Temperature at 10 A.M.: f(-7) = 61.91

   This value is 9.91 degrees higher than the actual value.

Step-by-step explanation:

With 1 am being timed as t = 1, we fitted the temperature data collected at different points during the day in Portland, Oregon using sine regression. After receiving the sine function, we respond to the many questions connected to the sine function's properties.

What is sinusoidal Function?

A smooth, repeating oscillation characterizes a sinusoidal function. Sine is an oscillation that is smooth and repeated, thus the name "sinusoidal." A pendulum swinging, a spring bouncing, or a guitar string vibrating are a few examples of commonplace objects that may be described by sinusoidal functions.

Given, The hourly temperature at Portland, Oregon, on a particular day is recorded.

Using sine regression on the given data with t = 1 being the hour 1 am etc, we get the following sine regression formula using the TI-83 Graphing Calculator where T is the temperature:

T = a sin(bt + c) + d

Where a = 19.65, b = 0.28, c = -2.93, d = 58.01

From the sine regression function above:

a. The amplitude of the sinusoidal function is a = 19.65.

b. The vertical shift is d = 58.01.

c. The period is 2*pi /b = 2*pi/ 0.28 = 22.44

d. At 5 PM, the time value is t = 17. Hence the temperature distribution with 5 PM being t = 0 will be

t = asin[b(t - 17) + c] +d.

e. From the table, at 10 AM, the actual value of the temperature is 52 degrees.

Using the model in part a., at 10 AM, with t = 10, the temperature will be

T = a sin(10b + c) + d

T = 55.46 degrees

Learn more about sinusoidal functions here:c. The period is

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Complete question:

Solve 6x+89(9)^2
3(2x+2403)
3(2x+234)
6x+7209
which one would it be

Answers

Answer:

It would be the last one 6x+7209

Step-by-step explanation:

because it will be simplify not factor by

Answer: The answer would be c

6x+7209

Step-by-step explanation:

since it would be like Isale said symplified and not factor by. In fact the deal of this question is that simplifying and factoring expressions are opposite processes so How do you know when to simplify? Well,  you will removing the pair of the parentheses.

What do you think about raising the minimum wage? What do you think would be some negative outcomes of raising the minimum wage? What are some positive outcomes of raising the minimum wage

Answers

We shouldn’t raise minimum wage, the reason for this being that when everyone makes more money prices on everything rise as well. So a negative effect could be prices increase and a positive effect could be something like people are now legally obliged to pay their workers more meaning you make more money.

8. The 2003 Zagat Restaurant Survey provides food, decor, and service ratings for some of the top restaurants across the United States. For 15 top-ranking restaurants located in Boston, the average price of a dinner, including one drink and tip, was $48.60. You are leaving for a business trip to Boston and will cat dinner at three of these restaurants. Your company will reimburse you for a maximum of $50 per dinner. Business associates familiar with these restaurants have told you that the meal cost at one-third of these restaurants will exceed $50. Suppose that you randomly select three of these restaurants for dinner. a) What is the probability that none of the meals will exceed the cost covered by your company

Answers

Answer:

0.2637

Step-by-step explanation:

Population size is top 15 ranking restaurants.

Number of draws = 3

Number of observed successes = 5

Probability formula :  [r . x } { n -r] [n - x]

solving the equation we get 24 / 91 which is approximately 0.2637

Evaluate the expression when y=-2.
y2 +6y-4

Answers

Answer:-12

Step-by-step explanation:

Perform the indicated operation.

Answers

Answer:

[tex] g(3) - h(3) = -16 [/tex]

Step-by-step explanation:

Given:

[tex] g(x) = 2x - 5 [/tex]

[tex] h(x) = 4x + 5 [/tex]

Required:

[tex] g(3) - h(3) [/tex]

SOLUTION:

Substitute x = 3 into [tex] g(x) = 2x - 5 [/tex]

[tex] g(3) = 2(3) - 5 [/tex]

[tex] g(3) = 6 - 5 [/tex]

[tex] g(3) = 1 [/tex]

Substitute x = 3 into [tex] h(x) = 4x + 5 [/tex]

[tex] h(3) = 4(3) + 5 [/tex]

[tex] h(3) = 12 + 5 [/tex]

[tex] h(3) = 17 [/tex]

Therefore:

[tex] g(3) - h(3) = 1 - 17 = -16 [/tex]

A train travelled 275 km in 2.5 hours how fast will the train go in an hour?

!!!!!!!!!

Answers

Answer: 110 mph

Step-by-step explanation: 275 / 2.5 = 110 mph

Find the next number in the pattern given below

-10, -2, 6, ____

Answers

-10 +8 = -2
-2 + 8 =6
6 + 8 = 14
answer is 14

Suppose an internet marketing company wants to determine the current percentage of customers who click on ads on their smartphones. How many customers should the company survey in order to be 90% confident that the estimated proportion is within five percentage points of the true population proportion of customers who click on ads on their smartphones

Answers

Answer:

The value is  [tex]n =271[/tex]  

Step-by-step explanation:

From the question we are told that

  The margin of error is  [tex]E = 5\% = 0.05[/tex]

From the question we are told the confidence level is  95% , hence the level of significance is    

      [tex]\alpha = (100 - 90 ) \%[/tex]

=>   [tex]\alpha = 0.10[/tex]

Generally from the normal distribution table the critical value  of  [tex]\frac{\alpha }{2}[/tex] is  

   [tex]Z_{\frac{\alpha }{2} } =  1.645[/tex]

Generally we will assume that the sample proportion is [tex]\^ p = 0.5[/tex] since we have no information on the proportion of  of customers who click on ads on their smartphones

Generally the sample size is mathematically represented as

      [tex]n = [\frac{Z_{\frac{\alpha }{2} }}{E} ]^2 * \^ p (1 - \^ p ) [/tex]

=>    [tex]n = [\frac{1.645 }}{0.05} ]^2 * 0.5 (1 - 0.5 ) [/tex]

=>    [tex]n =271[/tex]    

Using the z-distribution, as we are working with a proportion, it is found that 271 customers should be sampled.

What is a confidence interval of proportions?

A confidence interval of proportions is given by:

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

In which:

[tex]\pi[/tex] is the sample proportion.z is the critical value.n is the sample size.

The margin of error is given by:

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

In this problem:

90% confidence level, hence the critical value is z = 1.645.No prior estimate, hence p = 0.5.Within five percentage points, hence M = 0.05.

Then:

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

[tex]0.05 = 1.645\sqrt{\frac{0.5(0.5)}{n}}[/tex]

[tex]0.05\sqrt{n} = 0.5 \times 1.645[/tex]

[tex]\sqrt{n} = [10(1.645)][/tex]

[tex](\sqrt{n})^2 = [10(1.645)]^2[/tex]

[tex]n = 270.6[/tex]

Rounding up, 271 customers should be sampled.

More can be learned about the z-distribution at https://brainly.com/question/25890103

hello I need help on it pls ​

Answers

Answer:

19.5

Step-by-step explanation:

Use the figure to find the measures of the numbered angles.

Answers

Answer: 5=49, 6= 131

Step-by-step explanation:

0.079times what equals 7.9

Answers

Answer:

100

Step-by-step explanation:

The price of a pack of steaks increased from $15 to $21. By what percentage did the price of the pack of steaks increase?

Answers

Step-by-step explanation:

21 - 15 = 6$

you have to find how many percent is 6$ in 15$

6 ÷ 15 = 0.4

15 × 0.4 (40/100)

= 6

40 percent

Round 24,837,618 to the ten thousands place. I’m on math college so I need help on this problem!

Answers

Answer:

24,840,000

Step-by-step explanation:

Round up of numbers includes rounding them up to a given place value.

We are asked to round 24,837,618 to the ten thousands place.

The ten thousands place is the place where the number 3 in the number is located.

The number after 3 = 7 is a number above 5. Hence, we add 1 to 3, making it 4

Therefore, 24,837,618 to the ten thousands place is 24,840,000

Find the Sum:
(20 - 6) + 3(c + 8)

Answers

Answer:

38 + 3c

Step-by-step explanation:

Apply the distributed property: (20 - 6) + 3c + 2420 - 6 = 14Plug 14 in: 14 + 3c + 24Combine like terms: 38 + 3c

I hope this helps!

13(6x – 5) – x = 13 – 2(x + 1)

Answers

Answer:

x= 76/79

Step-by-step explanation:

isolate the variable by dividing each side by factors that don't contain a variable (x).

How do you find the whole in percent problems

Answers

Answer:

So essentially, you are trying to find what the overall whole is based off of a number that is the percent of the number. In order to do this, you must turn your percentage into a fraction over 100. You are going to then create the number that is a percentage of another number into a fraction over "x". Cross multiply the two fractions. Since there is an "x", count is as a zero. Now, create a fraction with the numerator as the number you just got from multiplying, and the denominator as the number you have to refer to as the percent of the whole. Since fraction is division, divide the two numbers and you get your answer. Sorry if this is so complex I tried to simplify it as best as I could

Step-by-step explanation:

Example: 8 is 80% of what number?

80% to 80/100

8 to 8/x

*cross multiply*

80x/80 = 800/80

800 divided by 80 is 10.

so, 8 is 80% percent of 10.

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