A cell phone company claims that the average time a person spends on their phone is 12.8 hours a week. A sample of unknown size of phone users was selected, and the mean time they spent on their phones was 12.2 hours in a week, with a standard deviation of 2.3 hours. Using a 90% confidence level, how many people would the company have to sample in order for their hypothesis to be true

Answer:

D ) none of these .. i think this help you

Answer:

-6

Step-by-step explanation:

27-3/2x=36

53-3x=72

3x=-18

x=-6

Answer:

1/4 cup each

Step-by-step explanation:

Take the amount of ice cream and divide by 3

3/4÷ 3

Copy dot flip

3/4 * 1/3

Rewriting

3/3 * 1/4

1/4 cup each

Answer:

4 scoops of ice cream

Step-by-step explanation:

Plug in the total cost, number of scoops of nuts, and number of liquid toppings into the formula. Then, solve for s:

C = 0.50s + 0.35n + 0.25t

3.55 = 0.50s + 0.35(3) + 0.25(2)

3.55 = 0.50s + 1.05 + 0.5

3.55 = 0.50s + 1.55

2 = 0.50s

4 = s

So, the sundae had 4 scoops of ice cream.

Answer:

Step-by-step explanation:

1500(1.055)^7= 2182.02

Answer:

B) 1 unit to the left

Step-by-step explanation:

Let W be the random variable representing your winnings from playing the game. Then

[tex]P(W=w)=\begin{cases}\text{prob. of rolling an even number}=\frac12&\text{if }w=\$0.50-\$1=-\$0.50\\\text{prob. of rolling a 1}=\frac16&\text{if }w=\$2-\$1=\$1\\\text{prob. of rolling 3 or 5}=\frac13&\text{if }w=\$1-\$1=\$0\\0&\text{otherwise}\end{cases}[/tex]

In short, you have a 1/6 chance of profiting from the game, and a 5/6 chance of losing money. So the odds of winning are (1/6)/(5/6) = 1/5 or 1 to 5.

Answer: No, there isn't equal opportunity

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

Explanation:

Let's define the two events

From the table, we see that

P(B) = 340/500 = 0.68

meaning that there's a 68% chance of picking someone who got the class they wanted (i.e. 68% of the people got the class they wanted)

------------

Now let's assume that the person is on the honor roll. This means we only focus on the "honor roll" column. There are 125 people here that got the class they wanted out of 205 honor roll students total.

So,

P(B given A) = 125/205 = 0.609756

which rounds to 0.61

This says that if a person is on the honor roll, then they have roughly a 61% chance of getting the class they want.

The chances have gone down from 68% to 61% roughly.

------------

It appears that being on the honor roll does affect your chances of getting into the class you want.

Therefore, all students do not have the same equal opportunity.

We would need to have P(B) and P(A given B) to be the same exact value for true equal opportunity to happen.

All students do not have equal opportunity.

From the table, we have the following parameters:

The above means that:

The probability that a person is on honor roll call is:

p1 = 205/500

p1 = 0.41

The probability that a person got the math class requested

p2 = 340/500

p2 = 0.68

Both probabilities are not equal.

Hence, it is true that all students do not have equal opportunity.

Read more about probability at:

https://brainly.com/question/25870256

Answer:[tex]n=\frac{58}{31}[/tex]

Step-by-step explanation:

[tex]124n=232\\\frac{124n}{124}=\frac{232}{124}\\n=\frac{232}{124}=\frac{58}{31}[/tex]

The value of n is 18.75. To find the value of n, we need to solve the equation: 124n = 232 five

Let's first convert "232 five" into a numerical value:

"232 five" means 2325 (since five is in the units place).

Now, the equation becomes:

124n = 2325

To solve for n, divide both sides of the equation by 124:

n = 2325 / 124

Now, perform the division:

n = 18.75

So, the value of n is 18.75.

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Answer:

26 cm

Step-by-step explanation:

P = 2a + 2b

a = side

b = base

Answer:

The area=base×height

=10×4

=40cm^2

perimeter=2(length+breadth)

I think to find the height Dc you use the pythagoras theorem of

Dc^2=de^2+ce^2

=√16+9

=5

therefore the perimeter will be

p=2(5+10)

=20cm

I hope this helps and sorry if it's wrong

Answer:

145

Step-by-step explanation:

Angles in a straight line = 180

So,

Let unkown angle be x,

x+35=180

x=180-35

x=145

Answer:

x = 74.74 m

Step-by-step explanation:

you need simple trigonometry to solve it

cosine of an angle is the ratio of the adjacent side to the hypotenuse

cos(42.2) is about 0.74

so X / Hypotenuse = 0.74

we know hypotenuse is 101 m

X / 101 = 0.74

x = 74.74 m

hope this helped!

Answer:

0.85714285714286 x 100 = 85.7143%.

Step-by-step explanation:

Answer:

i have attached pic of the graph

i hope this helps you

0.1449 = 14.49% probability that 6 students or more will score an "A" on the final exam.

---------------

For each student, there are only two possible outcomes. Either they score an A, or they do not. The probability of a student scoring an A is independent of any other student, which means that the binomial probability distribution is used to solve this question.

Additionally, to find the proportion of students who scored an A, the normal distribution is used.

----------------

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  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 a success.

----------------

Normal Probability Distribution

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

In a set with mean and standard deviation , 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.

----------------

Proportion of students that scored an A:

Scores have a mean of 79 and a standard deviation of 11.3, which means that [tex]\mu = 79, \sigma = 11.3[/tex]

Scores of 90 or higher are graded an A, which means that the proportion is 1 subtracted by the p-value of Z when X = 90, so:

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

[tex]Z = \frac{90 - 79}{11.3}[/tex]

[tex]Z = 0.97[/tex]

[tex]Z = 0.97[/tex] has a p-value of 0.8340.

1 - 0.8340 = 0.166

The proportion of students that scored an A is 0.166.

----------------

Probability that 6 students or more will score an "A" on the final exam:

Binomial distribution.

22 students, which means that [tex]n = 22[/tex]

The proportion of students that scored an A is 0.166, which means that [tex]p = 0.166[/tex]

The probability is:

[tex]P(X \geq 6) = 1 - P(X < 6)[/tex]

In which

[tex]P(X < 6) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5)[/tex]

Then

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

[tex]P(X = 0) = C_{22,0}.(0.166)^{0}.(0.834)^{22} = 0.0184[/tex]

[tex]P(X = 1) = C_{22,1}.(0.166)^{1}.(0.834)^{21} = 0.0807[/tex]

[tex]P(X = 2) = C_{22,2}.(0.166)^{2}.(0.834)^{20} = 0.1687[/tex]

[tex]P(X = 3) = C_{22,3}.(0.166)^{3}.(0.834)^{19} = 0.2239[/tex]

[tex]P(X = 4) = C_{22,4}.(0.166)^{4}.(0.834)^{18} = 0.2117[/tex]

[tex]P(X = 5) = C_{22,5}.(0.166)^{5}.(0.834)^{17} = 0.1517[/tex]

Then

[tex]P(X < 6) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) = 0.0184 + 0.0807 + 0.1687 + 0.2239 + 0.2117 + 0.1517 = 0.8551[/tex]

[tex]P(X \geq 6) = 1 - P(X < 6) = 1 - 0.8551 = 0.1449[/tex]

Thus

0.1449 = 14.49% probability that 6 students or more will score an "A" on the final exam.

For a problem that used the normal distribution, you can check https://brainly.com/question/15181104, and for a problem that used the binomial distribution, you can check https://brainly.com/question/15557838

Answer:

16

Step-by-step explanation:

Inverse variation is of the form

xy = k where k is a constant

x=4 and y = 32

4*32 = k

128 = k

xy = 128

Let x = 8

8y = 128

Divide each side by 8

8y/8 = 128/8

y =16

Answer:

Divide 79 by 8

Step-by-step explanation:

79/8

= 9.875

Answer:

-39

Step-by-step explanation:

Answer:

1/4

Step-by-step explanation:

Probability = 3/(5+3+4)

= 3/12 or 1/4

Answer:

The p-value of the test is 0.0007 < 0.01, which means that the class demonstrates that the percentage was higher in Owensboro, KY.

The possible proportion of patrons that do borrow books from the Owensboro Library is 0.82.

Step-by-step explanation:

For Americans using library services, the American Library Association claims that at most 67% of patrons borrow books. Test if the proportion is higher in Owensboro, KY.

At the null hypothesis, we test if the proportion is of at most 0.67, that is:

[tex]H_0: p \leq 0.67[/tex]

At the alternative hypothesis, we test if the proportion is of more than 0.67, that is:

[tex]H_1: p > 0.67[/tex]

The test statistic is:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.

0.67 is tested at the null hypothesis:

This means that [tex]\mu = 0.67, \sigma = \sqrt{0.67*0.33}[/tex]

The class randomly selected 100 patrons and found that 82 borrowed books.

This means that [tex]n = 100, X = \frac{82}{100} = 0.82[/tex]

Value of the test statistic:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \frac{0.82 - 0.67}{\frac{\sqrt{0.67*0.33}}{\sqrt{100}}}[/tex]

[tex]z = 3.19[/tex]

P-value of the test and decision:

The p-value of the test is the probability of a finding a sample proportion of 0.82 or above, which is 1 subtracted by the p-value of z = 3.19.

Looking at the z-table, z = 3.19 has a p-value of 0.9993.

1 - 0.9993 = 0.0007

The p-value of the test is 0.0007 < 0.01, which means that the class demonstrates that the percentage was higher in Owensboro, KY.

What is the possible proportion of patrons that do borrow books from the Owensboro Library?

The sample proportion of 0.82.

Answer:

120 ways

..................

Answer:

24

Step-by-step explanation:

4  friends

1st seat: 4 different people could sit here

Now there are 3 friends left

2nd seat: 3 different people could sit here

Now there are 2 friends left

3rd seat: 2 different people could sit here

Now there are 1 friends left

4th seat: 1 different people could sit here

4*3*2*1

24 ways

-105

Multiply first, then subtract, then add.

Answer: the answer would be -105.

The mass density in kg/m3 will be -  15 x [tex]10^{-2}[/tex] Kg/m3.

We have a 100.0 m long polymer cable of uniform circular cross section and of diameter 0.4cm has a mass of 1885.0 gm.

We have to determine its mass density in kg/m3.

The amount of mass per unit volume present in the body is called its mass density.

According to question, we have -

Length of polymer cable = 100.0 m

diameter of polymer cable = 0.4 cm = 0.004 m

Therefore, its radius = 0.002 m

The mass density of the wire will be -

[tex]\rho =\frac{m}{\pi r^{2} l}[/tex]

[tex]\rho[/tex] = [tex]\frac{1885}{3.14 \times0.002 \times 0.002 \times 100 }[/tex]

[tex]\rho = \frac{1885}{0.001256}[/tex] = 1500796.1 g/m3

1 Kg = 1000g

1g = 1/1000kg

1500796.1g = 1500.7 Kg = 15 x [tex]10^{-2}[/tex] Kg

Therefore, mass density = 15 x [tex]10^{-2}[/tex] Kg/m3

Hence, the mass density in kg/m3 will be -  15 x [tex]10^{-2}[/tex] Kg/m3.

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Answer:

15 years

Step-by-step explanation:

Given the quadratic regression model:

y = 8x² - 40x+6 ; where

y = Number of people attending graduate school ;

x = number of years

The value of x when y = 1206

The equation becomes :

1206 = 8x² - 40x+6

1206 - 6 = 8x² - 40x

1200 = 8x² - 40x

Divide through by 8

150 = x² - 5x

x² - 5x - 150 = 0

x² - 15x + 10x - 150 = 0

x(x - 15) + 10(x - 15)

x - 15 = 0 or x + 10 = 0

x = 15 or x = - 10

Number of years can't be negative,

Hence, x = 15 years

The rate of change of R with time in the given equation is 0.004 ohm/s

Given parameters:

[tex]\frac{1}{R} = \frac{1}{R_1} + \frac{1}{R_2} \\\\\frac{dR_1}{dt} = 0.3 \ ohm/s\\\\\frac{dR_2}{dt} = 0.2 \ ohm/s\\\\R_1 = 60 \ ohms\\\\R_2 = 80 \ ohms[/tex]

To find:

First determine the value of R from the given equation;

[tex]\frac{1}{R} = \frac{1}{R_1} + \frac{1}{R_2} \\\\\frac{1}{R} = \frac{1}{60} + \frac{1}{80} \\\\\frac{1}{R} = \frac{4 + 3}{240} \\\\\frac{1}{R} = \frac{7}{240} \\\\R = \frac{240}{7} = 34.286 \ ohms[/tex]

Finally, to determine the rate of change of R, differentiate the given equation.

[tex]\frac{-1}{R^2} \frac{dR}{dt} = \frac{-1}{R_1^2} \frac{dR_1}{dt} - \frac{1}{R_2^2} \frac{dR_2}{dt} \\\\\frac{1}{R^2} \frac{dR}{dt} = \frac{1}{R_1^2} \frac{dR_1}{dt} + \frac{1}{R_2^2} \frac{dR_2}{dt}\\\\\frac{dR}{dt} = R^2(\frac{1}{R_1^2} \frac{dR_1}{dt} + \frac{1}{R_2^2} \frac{dR_2}{dt})[/tex]

[tex]\frac{dR}{dt} = 34.286(\frac{1}{(60)^2} \times 0.3 \ \ \ + \ \ \ \frac{1}{(80)^2} \times 0.2)\\\\\frac{dR}{dt} = 34.286(8.333 \times 10^{-5} \ \ \ + \ \ \ 3.125 \times 10^{-5})\\\\\frac{dR}{dt} = 34.286(11.458 \times 10^{-5})\\\\\frac{dR}{dt} = 0.00393\\\\\frac{dR}{dt} \approx 0.004 \ ohm/s[/tex]

Thus, from the given equation the rate of change of R with time is 0.004 ohm/s

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Answer:

the verified answer is wrong.

Step-by-step explanation:

OP forgot to square R (34.286)

Answer:

The polygon consists of 6 sides and the given polygon is a regular hexagon.

Step-by-step explanation:

The definition of perimeter is the total measure of the side lengths of a polygon. If the polygon said is regular, it means the polygon has equal sides and equal angles.

So the perimeter of a regular polygon is given by the formula:

P = (length of one side) x (number of sides)

In this case, the perimeter of the polygon is 19.2 cm and one side is equal to 3.2 cm.

DIVIDE (use the formula but in division to maintain a proportonal relationship):

19.2 ÷ 3.2 = 6

You could alsk check if its correct using the formula:

19.2 = 3.2 x 6 (TRUE)

A 6 sided regular polygon is known as a HEXAGON.

Hope this helps!

Answer:

sin ß = opposite / hypotenuse

sin45° = x / 4√2

Cross multiply

x = sin 45° × 4√2

x = √2/2 × 4√2

x = 4 × √2 ×√2 / 2

x = 4 × 2 / 2

x = 8 / 2

x = 4