Suppose that 200 students are randomly selected from a local college campus to investigate the use of cell phones in classrooms. When asked if they are allowed to use cell phones in at least one of their classes, 40% of students responded yes. Using these results, with 95% confidence, the margin of error is 0.068. How would the margin of error change if the sample size increased from 200 to 400 students?

Answers

Answer 1

Answer:

It would change to 0.04802

Step-by-step explanation:

from this question we have that n became 400

40% of 400

= 160

p* = 160/400

= 0.4

1 - p* =

= 1 - 0.4

= 0.6

at confidence level,

1 - 0.95

= 0.05

alpha/2 = 0.025

z= 1.96

margin of error. E

= 1.96 x √[(0.4 x 0.6)/400]

= 1.96 x 0.0245

= 0.04802

M.E = 0.04802


Related Questions

How long will it take for a lump-sum investment to double in value at an interest rate of 1.5% per month, compounded continuously

Answers

Answer:

It will take 47 months ( 3 years and 11 months)

Step-by-step explanation:

We use the compound interest formula here.

Mathematically;

A = P( 1 + r)^t

Where A is the amount which is 2 times the principal here, so we can call it 2P

P is the lump-sum invested

r is the monthly interest rate given as 1.5% = 1.5/100 = 0.015

t = time , which we want to calculate

Substituting these values, we have;

2P = P(1 + 0.015)^t

divide both sides by P

2 = 1.015^t

Take the log of both sides;

log 2 = log (1.015)^t

log 2 = t log 1.015

t = log2/log1.015

t = 46.55

which is approximately 47 months

Can someone please help me with this question?

Answers

Answer:

B

Step-by-step explanation:

11q + 5 ≤ 49

Subtract 5 from each side

11q + 5-5 ≤ 49-5

11q ≤44

Divide each side by 11

q ≤44/11

q≤4

There is a close circle at 4 because of the equals sign and the lines goes to the left

Answer:

B

Step 1:

To solve this, we need to isolate the variable q. To do so, we will subtract 5 from both sides of the inequality.

[tex]11q+5(-5)\leq 49(-5)\\11q\leq 44[/tex]

Step 2:

We divide both sides by 11 to get our q.

[tex]\frac{11q}{11}\leq \frac{44}{11} \\q\leq 4[/tex]

q ≤ 4

Step 3:

To find the correct graph, we need to know that a close circle means a ≤ or ≥ and an open one means a < or >. Here, we are using a ≤ so C and D are not our answers. Also remember that if the "arrow" is pointing left (<), then the arrow on the graph should be facing the left side. If the arrow is facing the right side, then that means we are using > or ≥. Here, we are using ≤ (left), so that means the arrow on the graph should be on a 4, facing left, with a closed circle.

Our answer is B.

marc mixes blue and yelow paint to ,ake green he has 14 cans blue 20 cans of yellow . he wants green color so one day 1 he mixes 4 blue 6 yellow day 2 he mixes 6 can blue 9 yellowwhats the highest number of cans each color marc can mix to mzke the same shade of green on day 3

Answers

Answer:

2  c an of blue and 5 can of yellow

Step-by-step explanation:

identify the decimals labeled with the letters A, B, and C on the scale below. Letter A represents the decimal Letter B represents the decimal Letter C represents the decimal

Answers

[tex]10[/tex] divisions between $20$ and $20.1$ so each division is $\frac{20.1-20.0}{10}=0.01$

A is 2nd division from $20.0$, so, A is $20.0+2\times 0.01=20.02$

similarly, C is one division behind $20.0$ so it is 19.99

and B is $20.14$

Which of the following best represents the average rate at which the human hair grows?

Answers

Answer:

1/2 inch per month

Step-by-step explanation:

The average rate hair grows is about half an inch per month which is 6 inches per year.

A half inch every month

Even though the population standard deviation is unknown, an investigator uses z rather than the more appropriate t to test a hypothesis at the .01 level of significance. In this situation the true level of significance of this test is

Answers

Answer:

The true true level of significance of this test is more than 0.01.

Step-by-step explanation:

No standard deviation and we are told that the investigator still used z rather than the more appropriate t - distribution.

This method of using the z-distribution when standard deviation is unknown will definitely result in a smaller critical value and this in turn simply means that the p-value will be smaller than what it should really be.

Thus, it means the critical value is getting closer to the mean value than the way it should be.

Therefore, means that for a given significance of 0.01 and using the z-distribution under this no standard deviation situation, the true true level of significance of this test is more than 0.01.

A certain family has a husband, wife, son, and daughter. All together they are 68 years old. The husband is 3 years older than the wife, and the son is 3 years older than the daughter. Four years ago, all together the family was 54 years old. How old is the husband now?

Answers

Answer:

32 years old

Step-by-step explanation:

The husband is 32 years old as the wife is 3 years younger than the husband. The son is 3 years older than the daughter. Their family altogether total age today is 68 years while 4 years ago their age total was 54 years. The difference is 14 years. If we divide the difference into 4 then the age can not be whole number which means daughter is born after 2 years. She is now 2 years older. Son is 3 years older than the daughter which means he is 5 years old. The husband then must be 32 years old and wife is 3 years younger which means she is 29 years old now.

32 + 29 + 5 + 2 = 68 years.

The one-sample z test is: a. a hypothesis test b. used to test hypotheses c. concerning a single population with a known variance d. concerning at least one population e. concerning the variance in a population d. all of the above

Answers

Answer:

d. all of the above

Step-by-step explanation:

A one sample z test measures whether the mean of a population is greater, less or equal to a specific value. It is called one sampl z test since the standard normal distribution is used in calculation of critical values. It makes use of the null hypothesis and alternative hypothesis in determining if the mean is greater than or equal or less than the reference value. Variance and standard deviation is assumed to be known and at least one population is used

if the sin 30 = 1/2, then which statement is true?

Answers

Answer:

cos 60° = 1/2 because the angles are complements.

Step-by-step explanation:

Which graph has an amplitude of 1/2?

Answers

Answer:

Step-by-step explanation:

The only graph shown in the question doesn't have amplitude 1/2. look for a graph of a periodic wave function that has maximum y-value 1/2 (0.5) and minimum y-value 1/2 (0.5), or if it is not oscillating around the x-axis, verifies that the distance between minimum y-value and maximum y-value is "1" (one). This is because the amplitude is half of the peak-to-peak distance.

Look at the attached image as example.

Answer:

Answer is B

Step-by-step explanation:

Did it on Edge

A number to be multiplied is called a?

Answers

Answer:

The number to be multiplied is the "multiplicand"

Step-by-step explanation:

a base when it is written in exponential notation

The price of a technology stock was $ 9.56 yesterday. Today, the price rose to $ 9.69 . Find the percentage increase. Round your answer to the nearest tenth of a percent.

Answers

Answer and Step-by-Step explanation:

% increase = 100 x [(new price) - (original price)] / (original price)] = 100 (9.67 - 9.56) / 9.56

% increase ≅ 1.2% (to the nearest tenth)

Find the total surface area of the farm silo in a farmer's field. Use π = 3.14. pls help asap uwu

Answers

Answer:

A) 1236 units²

Step-by-step explanation:

Cylinder = 2[tex]\pi[/tex]h+2[tex]\pi[/tex]r²

2(3.14)(7.5)(15)+2(3.14)(7.5x7.5)

706.5+353.25=1059.75

1/2 Sphere = 1/2(4)[tex]\pi[/tex]r²

2(3.14)(7.5)(7.5)

353.25

TOTAL: 1059.75+353.25=1413

HOWEVER...you need to subtract the top of the cylinder ([tex]\pi[/tex]r²) 176.625

1413-176.625=1236.375

So the answer would be A.  (Silo’s do have a bottom, or else the answer would be D)

Answer:

1,236 units²

Step-by-step explanation:

I got it correct on founders edtell and screenshot below as proof

A baseball player has a batting average of 0.26. What is the probability that he has exactly 6 hits in his next 7 at bats

Answers

Answer:

0.0016

Step-by-step explanation:

Batting average, p = 0.26

n = 7

x = 6

With p = 0.26 as success rate

1-p is equal to failure rate which is = 0.74

We have to solve this by using the binomial distribution formula.

P(X= x)

= nCx * p^x * (1-p)^(n-x)

P(X = 6)

=7C6 × 0.26^6 ×(1-0.26)^(7-6)

= 7 × 0.0003089 × 0..74¹

= 0.0016

So probability that he has exactly 6 hits in his next 7 bats is equal to 0.0016.

A collector as a set of 224 coins. Some are valued at 20 cents and others at 25 cents. If the collector has 74 25-cent coins, then what is the total value of the collection

Answers

Answer:

48.50 dollars.

Step-by-step explanation:

The collector has a total of 224 coins but 74 of them are 25 cents coins. So, in order to find the number of 20-cent coins we're going to subtract the number of 25-cent coins from the total.

Number of 20-cent coins = 224 - 74 = 150.

Thus, the collector has 150 20-cent coins and 74 25-cent coins for a total of 224 coins.

Now, to know the total value of the collection we need to multiply the value of the coins by the number of coins there are of this value (we are going to do it with the 20-cent and the 25-cent coins) and then sum up our results.

Total value = 74(25) + 150 (20) = 1850 + 3000 = 4850 cents.

So the total value is 4850 cents, we know that each dollar has 100 cents so, to express this number in dollars we are going to divide it by 100 and thus we have that the total value of the collection is 48.50 dollars.

Extensive experience with fans of a certain type used in diesel engines has suggested that the exponential distribution provides a good model for time until failure. Suppose the mean time until failure is 23,100 hours.

(a) What is the probability that a randomly selected fan will last at least 20,000 hours?


What is the probability that a randomly selected fan will last at most 30,000 hours?


What is the probability that a randomly selected fan will last between 20,000 hours and 30,000 hours?


(b) What is the probability that the lifetime of a fan exceeds the mean value by more than 2 standard deviations?


What is the probability that the lifetime of a fan exceeds the mean value by more than 3 standard deviations?

Answers

Answer:

0.4207149;0.7271136; 0.3063987; 0.04979 ; 0.01832

Step-by-step explanation:

For an exponential distribution:

IF Mean time until failure = 23100

λ = 1/ 23100 = 0.0000432900

What is the probability that a randomly selected fan will last at least 20,000 hours

x ≥ 20000

P(X ≥ 20000) = 1 - P(X ≤ 20000)

1 - P(X ≤ 20000) = [1 - (1 - e^(-λx))]

1 - P(X ≤ 20000) = [1 - (1 - e^(-0.0000432900*20000)

1 - P(X ≤ 20000) = [1 - (1 - 0.4207148)]

1 - P(X ≤ 20000) = 1 - 0.5792851

1 - P(X ≤ 20000) = 0.4207149

11) What is the probability that a randomly selected fan will last at most 30,000 hours?

x ≤ 30000

P(X ≤ 30000) = 1 - e^(-λx)

P(X ≤ 20000) = 1 - e^(-0.0000432900*30000)

= 1 - e^(−1.2987)

= 1 - 0.2728863

= 0.7271136

111) What is the probability that a randomly selected fan will last between 20,000 hours and 30,000 hours?

0.7271136 - 0.4207149 = 0.3063987

B) What is the probability that the lifetime of a fan exceeds the mean value by more than 2 standard deviations?

More than two standard deviation

X = 23100 + 2(23100) = 23100 + 46200 = 69300

Using the online exponential probability calculator :

P(X > 69300) = 0.04979

C) What is the probability that the lifetime of a fan exceeds the mean value by more than 3 standard deviations?

X = 23100 + 3(23100) = 23100 + 69300 = 92400

P(X > 92400) = 0.01832

Solve the equation 3(2x + 2) = 3x − 15.

Answers

Hi there! :)

Answer:

x = -7.

Step-by-step explanation:

Starting with:

3(2x + 2) = 3x - 15

Begin by distributing '3' with the terms inside of the parenthesis:

3(2x) + 3(2) = 3x - 15

Simplify:

6x + 6 = 3x - 15

Isolate the variable by subtracting '3x' from both sides:

6x - 3x + 6 = 3x - 3x - 15

3x + 6 = -15

Subtract 6 from both sides:

3x + 6 - 6 = -15 - 6

3x = -21

Divide both sides by 3:

3x/3 = -21/3

x = -7.

Answer:

x = -7

Step-by-step explanation:

3(2x+2) = 3x - 15

First, we should simplify on the left side.

6x + 6 = 3x - 15 ; Now we subtract six from both sides.

      -6          -6

6x = 3x - 21 ; next we just subtract 3x from both sides.

-3x   -3x

3x = -21

Finally, we divide 3 from both sides to separate the three from the x.

x = -7

Hope this helps!! <3 :)

Show that the set of functions from the positive integers to the set {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} is uncountable. [Hint: First set up a one-to-one correspondence between the set of real numbers between 0 and 1 and a subset of these functions. Do this by associating to the real number 0.d1d2 . . . dn . . . the function f with f(n).

Answers

Answer:

since the set of functions expressed are uncountable and they are a subset of real numbers starting from N therefore the set {0,1,2,3,4,5,6,7,8,9} is uncountable as well as its off functions

Step-by-step explanation:

set = {0,1,2,3,4,5,6,7,8,9}

setting up a one-to-one correspondence between the set of real numbers between 0 and 1

The function : F(n)= {0,1} is equivalent to the subset (sf) of (n) , this condition is met if n belongs to the subset (sf) when f(n) = 1

hence The power set of (n) is uncountable and is equivalent to the set of real numbers given

since the set of functions expressed are uncountable and they are a subset of real numbers starting from N therefore the set {0,1,2,3,4,5,6,7,8,9} is uncountable as well as its offfunctions

The lower edge of a 5 foot tall painting is 5 feet above your eye level. At what distance should you stand from the wall so your viewing angle of the painting is maximized?

Answers

Answer:

x = sqrt(50) = 5sqrt(2) = 7.071 ft (to 3 decimals)

Step-by-step explanation:

referring to the diagram

theta (x) = atan(10/x) - atan(5/x)

differentiate with respect to x

theta'(x) = 5/(x^2+25) - 10/(x^2+100)

For x to have an extremum (max. or min)

theta'(x) = 0  ="

5/(x^2+25) - 10/(x^2+100) = 0

transpose and cross multiply

10(x^2+25) -5(x^2+100) = 0

expand and simplify

10x^2+250 - 5x^2-500 = 0

5x^2 = 250

x^2=50

x = sqrt(50) = 5sqrt(2) = 7.071 ft (to 3 decimals)

Since we know that if x becomes large, theta will decrease, so

x = 5sqrt(2) is a maximum.

The driveway needs to be resurfaced. what is the BEST estimate of the area of the driveway?​

Answers

Answer:

125π ft²

Step-by-step explanation:

1/4π(30)² - 1/4π(20)² = 125π

A researcher is interested in determining whether typists are most productive in the morning, at midday, in the evening, or late at night. To answer this question, the researcher recruits 20 participants and assigns 5 participants to be measured at each time of day. To evaluate productivity, the researcher measures words typed per minute at each time of day.
Morning Midday Evening Night
99 42 80 82
80 32 83 78
99 45 94 79
98 49 70 97
79 38 79 96
Mean 91 41.2 81.2 86.4
SStotal = 9094.95
What are the degrees of freedom for the numerator of the F-ratio?
a. 2
b. 3
c. 16
d. 19

Answers

Answer:

d. 19

Step-by-step explanation:

Degrees of freedom is the number is the number of value which is used in the final calculation. It calculate as n-1, where n is the sample size. The degrees of freedom for the given scenario is 19. The sample size is 20 so the degrees of freedom is 1 less which will be 19.

Sarah knows how important it is to budget her monthly expenses. She earns $3,120 every month and her monthly expenses total to $2,130. Sarah has summarized her monthly expenses using the pie chart below. What percent of Sarah's monthly income is left over after she pays her monthly bills? Round to the dollar​

Answers

Answer: 37.1%

Step-by-step explanation:

2130/3120×100% = 68.3%

100% - 68.3%

=31.7%

37.1%

which makes that $460

May I have brainliest please? :)

Also, the person above me smells like how a diaper tastes

The one-sample z ‑statistic for Thomas' statistical test has a value of −1.73346 , and Thomas calculates a P-value of 0.0830 . Should Thomas conclude that telephone surveys provide adequate coverage with respect to p ? Why or why not? Select all correct statements about his decision and conclusion.

Answers

Answer:

Thomas should not reject the null hypothesis.

Step-by-step explanation:

The null hypothesis is rejected or accepted on the basis of level of significance. When the p-value is greater than level of significance we fail to reject the null hypothesis and null hypothesis is then accepted. It is not necessary that all null hypothesis will be rejected at 10% level of significance. To determine the criteria for accepting or rejecting a null hypothesis we should also consider p-value.  Here in this question the test value is -1.73346 and p-value is 0.0830. The p value is greater than the test value therefore the null hypothesis should be accepted.

Find x in each triangle. PLZ ANSWER FAST!!!!!!!!!!!

Answers

a) a^2 + b^2 = c^2
c^2 - a^2 = b^2
13^2 - 5^2 = b^2
b = 12dm

b) a^2 + b^2 = c^2
10^2 + 24^2 = c^2
c = 26 in

c) a^2 + b^2 = c^2
c^2 - a^2 = b^2
17^2 - 8^2 = b^2
b = 15 ft

Is {(4,2),(4,-2),(9,3),(9,-3)} a function

Answers

Answer:

  no

Step-by-step explanation:

If any x-value is repeated, the relation is not a function. Both x=4 and x=9 are repeated values, so this relation is not a function.

If sin∠M = cos∠N and m∠N = 30°, what is the measure of ∠M?

Answers

Step-by-step explanation:

sin∠M = cos∠N

sin∠M = cos(30°)

sin∠M = √3 / 2

m∠M = 60° or 120°

If ∠M is acute, m∠M = 60°.

Answer: The measure of ∠M is 60°

Step-by-step explanation:

The complement of 30° is 60°

sin∠M =cos∠N

sin∠60°=cos∠30°

the measure of ∠M is 60°

In this problem, we explore the effect on the mean, median, and mode of adding the same number to each data value. Consider the data set 6, 6, 7, 10, 14.

Answers

Answer

The mean is 8.6

The median is 7

And the mode is 6

What number should both sides of the following equation be multiplied by to solve for g? g divided by 2 = 4

Answers

Answer: Multiply both sides by 2.

Step-by-step explanation:

g divided by 2  is equal to 4 .

We could represent that with the equation :

[tex]\frac{g}{2} = 4[/tex]     To solve for g  in this case multiply both sides by 2.

[tex]\frac{g}{2} * 2 = 4(2)[/tex]     2 cancels out on the left side so we will be left with g. On the right side will be left with 8  after multiplying.

g = 8    

Relating a Polynomial Identity to Pythagorean Triples
In this activity you'll relate polynomial identities with Pythagorean triples. Answer the following questions
based on this triangle with side lengths x^2 – 1, 2x, and x^2 + 1.

Answers

Answer:

Step-by-step explanation:

Hello, please consider the following.

For x > 1, we can apply Pythagoras theorem as below.

[tex]\text{Let's estimate this sum of two squares.} \\\\(2x)^2+(x^2-1)^2=4x^2+x^4-2x^2+1=x^4+2x^2+1\\\\\text{Let's estimate this square, now.} \\\\(x^2+1)^2=x^4+2x^2+1\\\\\text{The two expressions are equal, meaning.} \\\\(2x)^2+(x^2-1)^2=(x^2+1)^2\\\\\text{Using Pythagoras' theorem, we can say that this is a right triangle.}[/tex]

Thank you

Find the length of GV¯¯¯¯¯¯¯¯ A. 43.92 B. 33.1 C. 41.45 D. 68.87

Answers

Answer:

The answer is option A

Step-by-step explanation:

Since the figure above is a right angled triangle we can use trigonometric ratios to find GV

To find GV we use cosine

cos∅ = adjacent / hypotenuse

From the question

GV is the adjacent

GC is the hypotenuse

So we have

[tex] \cos(37) = \frac{GV}{GC} [/tex]

GC = 55°

GV[tex] \cos(37) = \frac{GV}{55} [/tex]

GV = 55 cos 37

GV = 43.92495

We have the final answer as

GV = 43.92

Hope this helps you

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