3. university dean of students wishes to estimate the average number of hours students spend doing homework per week. The standard deviation from a previous study is 4 hours. How large a sample must be selected if he wants to be 96% confident of finding whether the true mean differs from the sample mean by 2 hours

Answers

Answer 1

Answer:

A sample of 17 must be selected.

Step-by-step explanation:

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1 - 0.96}{2} = 0.02[/tex]

Now, we have to find z in the Z-table as such z has a p-value of [tex]1 - \alpha[/tex].

That is z with a pvalue of [tex]1 - 0.02 = 0.98[/tex], so Z = 2.054.

Now, find the margin of error M as such

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.

The standard deviation from a previous study is 4 hours.

This means that [tex]\sigma = 4[/tex]

How large a sample must be selected if he wants to be 96% confident of finding whether the true mean differs from the sample mean by 2 hours?

A sample of n is required.

n is found for M = 2. So

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

[tex]2 = 2.054\frac{4}{\sqrt{n}}[/tex]

[tex]2\sqrt{n} = 2.054*4[/tex]

Simplifying both sides by 2:

[tex]\sqrt{n} = 2.054*2[/tex]

[tex](\sqrt{n})^2 = (2.054*2)^2[/tex]

[tex]n = 16.88[/tex]

Rounding up:

A sample of 17 must be selected.


Related Questions

The diagram below is divided into equal parts. Which fraction of the parts is white?

A diagram is divided into 4 blue parts and 3 white parts.
Three-sevenths
Four-sevenths
Three-fourths
Four-thirds

Answers

Answer: This problem is a fraction since we have several equal parts that make up one whole. The problem asks us to talk about the relationship of white pieces to the whole. Since we know the whole is made up of 7 pieces (4 blue parts and 3 white parts = 7 total parts), then 7 will be our denominator (number on the bottom of the fraction).

Now that we have our number on the bottom, we need to look back at the question to carefully decide what parts of the whole we are looking at. The question wants to know how many of the parts are white. We know that 3 of the parts are white, so that is our numerator (number of the top of the fraction).

Our final answer is 3/7 or "three-sevenths." Said another way, three of the seven pieces are white.

Step-by-step explanation:

The quadratic function f(x) = -x2 - 6x - 8 is graphed.
What are the solutions of the quadratic equation 0 =
x2 - 6x - 8?
Ту
2
O 2 and 4
0-2 and 4
0-2 and 4
O: 2 and 4
6 5 A
-3
-1
X
-2
ون

Answers

Answer:

-2 and -4

Step-by-step explanation:

When the quadratic equation equals 0, that means when y = 0.

By looking at the graph, whenever y = 0 is when the graph crosses the x-axis.

The graph crosses the x-axis at only two points:

(-4, 0) and (-2, 0)

So the solutions to the graph when  -x^2 - 6x - 8 equals 0 is -2 & -4.

Hope it helps (●'◡'●)

Answer:

-2 and -4

Step-by-step explanation:

if you'll notice the function goes through the x axis at -2 and -4

A number is divisible by 3 if the sum of the digits of the number is divisible by 3.

Answers

I believe the answer the the question A number is divisible by 3 if the sum of the digits of the number is divisible by 3. Is 504, it makes sense

Find two positive numbers whose product is 64 and whose sum is a minimum. (If both values are the same number, enter it into both blanks.) (smaller number) (larger number)

Answers

Answer:

Both the numbers are 8.

Step-by-step explanation:

Let the two numbers are p and 64/p.

The sum is given by

[tex]S = p +\frac{64}{p}\\\\\frac{dS}{dp}= 1 - \frac{64}{p^2}\\\\\frac{dS}{dp}=0\\\\\frac{64}{p^2}=1\\\\p= \pm 8[/tex]

So, the sum is minimum for p = 8 0r - 8, so the two numbers 8.

How many fourths are in 3 4 ?
O 4 Over 16
O One-half
O 3
O 4

Answers

Answer:

⭕ 3

hope it helps much

what is 1.8 in written notation

Answers

Answer:

The answer is 1/8

A boy leaves station X on a bearing of 035' to station Y. which is 21km away. He then travels to another station Z on a bearing of 125 degrees . If Z is directly East of X, what is the distance from X to his present position?​

Answers

9514 1404 393

Answer:

  36.6 km

Step-by-step explanation:

We assume the initial bearing of the boy is 35°. Then he will make a 90° turn to a heading of 125°. A diagram shows the distance of interest is the hypotenuse of a right triangle in which 35° is the angle opposite the side of length 21 km.

The relevant trig relation is ...

  Sin = Opposite/Hypotenuse

  sin(35°) = (21 km)/XZ

  XZ = (21 km)/sin(35°) ≈ 36.61 km

The distance from X to Z is about 36.61 km.

_____

The attached diagram has the angles measured in the usual way for a Cartesian plane: CCW from the +x axis. This will correspond to bearing measures if we relabel the axes so that +x is North, and +y is East.

By way of tree diagram determine all likely outcome when a fair die is tossed

Answers

Step-by-step explanation:

hope it helps

brainliest please

2x + 2x + 5x + 5x= please answer quick it's very hard and I like the game to answer please and thank you.

Answers

Answer:

14x I answered your question thank you for the points appreciate it

Answer:

2x+2x+5x+5x=14x

Ans: 14x

suppose △abc≅△xyz. what is the corresponding congruent part for each segment or angle?​

Answers

Answer:

Step-by-step explanation:

Find the angle θ between ???? and ???? if ????⋅????=12‖????‖⋅‖????‖. (Use symbolic notation and fractions where needed. Give your answer in terms of π. )

Answers

Answer: hello your question is poorly written below is the complete question

Find the angle between and if ⋅=3√2‖‖⋅‖‖.

(Use symbolic notation and fractions where needed. Give your answer in terms of . )

answer :

∅ = π / 6

Step-by-step explanation:

V .W = [tex]\frac{\sqrt{3} }{2} || V ||. ||W||[/tex]

Hence

∅ = cos^-1 ( [tex]\frac{\frac{\sqrt{3} }{2} || V ||. ||W||}{||V||.||W||}[/tex]

∅ = cos^-1 ( [tex]\frac{\sqrt{3} }{2}[/tex] )

∴ ∅ = π / 6

Si dos angulos son conjugados entre paralelas entonces son suplementarios es verdadero o falso

Answers

Si dos angulos son conjugados entre paralelas entonces son suplementarios es verdadero o falso

Step-by-step explanation:

no worries skills development and implementation of the year in a while and I am looking for an appointment with the other day

sum of first n terms of an ap sequance is 3n2+5n.what is the sum of its first n+1 terms.find the sum of its first 10 terms.



Answers

Answer:

a) 3n^2 + 11n + 8

b) 350

Step-by-step explanation:

10) 3(10^2)+ 5*10 = 350

n+1) 3(n+1)^2 + 5(n+1)

        3(n^2 + 2n + 1) + 5n+5

         3n^2 + 6n+3 + 5n + 5

           3n^2 + 11n + 8

Determine if each statement is always, sometimes, or never true.

Parallel lines are
coplanar.

Perpendicular lines are
coplanar.

Distance around an unmarked circle can
be measured

Answers

Answer:

1) Parallel lines are "ALWAYS"

coplanar.

2) Perpendicular lines ARE "ALWAYS"

coplanar.

3) Distance around an unmarked circle CAN "NEVER" be measured

Step-by-step explanation:

1) Coplanar means lines that lie in the same plane. Now, for a line to be parallel to another line, it must lie in the same plane as the other line otherwise it is no longer a parallel line. Thus, parallel lines are always Coplanar.

2) similar to point 1 above, perpendicular lines are Coplanar. This is because perpendicular lines intersect each other at right angles and it means they must exist in the same plane for that to happen. Thus, they are always Coplanar.

3) to have the distance, we need to have the circle marked out. Because it is from the marked out circle that we can measure radius, diameter and find other distances around the circle. Thus, distance around an unmarked circle can never be measured.

8. Discount: An auto dealer paid $8730 for a
large order of special parts. This was not the
original price. The amount paid reflects a 3%
discount off the original price because the
dealer paid cash. What was the original price
of the parts?

Answers

Answer: 5,987

Step-by-step explanation:

Can someone answer these?

Answers

Answer: hello there here are your answers:

5.d associate property of addition

6.b multiplicative identify

7. c Additive identify

Step-by-step explanation:

5) they are just changing up the number in the ()

6) Its the same number or equation on both sides just wrote different

7) that in a given mathematical system leaves unchanged any element to which it is added.

hope this help have a good day bye!

Find the value of y .
Please help !

Answers

9514 1404 393

Answer:

  (b)  √55

Step-by-step explanation:

The right triangles in this geometry are all similar, so the ratio of long side to short side is the same:

  y/5 = 11/y

  y² = 55 . . . . . . multiply by 5y

  y = √55 . . . . . take the square root

__

And x=4√5 by looking at ratios of short side to hypotenuse.

19. Divide 6/13 by 6/12.
A. 12/13
B. 13/12
c. 1/12
D.9/16

Answers

Answer:

12/13 is the answer

Step-by-step explanation:

I think the answer is A . 12/13

Suppose your dean of admissions is considering surveying high school seniors about their perceptions of your school to design better informational brochures for them. What are the advantages and disadvantages of doing (a) telephone interviews and (b) an Internet survey of seniors who have requested information about the school

Answers

Answer and explanation:

Advantages of telephone interviews:

They are more convenient than face to face interviews

They are alot more cost-effective

There is a wider geographical access as you can reach people in other countries too

Disadvantages of telephone interviews:

Questions become has limited complexity as opposed to face to face interviews

It may be somewhat intrusive for customers and there could also be interference from noise in the background. Also bad connection issues.

Advantages of internet survey:

Increased geographical access leading to high response rate.

Alot more convenient and flexible than face to face interviews

Low cost advantages

Disadvantages of internet survey:

Inability for individuals who are not online to participate

Non response bias

Limited complexity of questions, usually close ended questions

what is the LCM of 2 Express on if there is no common factor​

Answers

Answer:

I started by dividing 2940 by the smallest prime that would fit into it, being 2. This left me with another even number, 1470, so I divided by 2 again. The result, 735, is divisible by 5, but 3 divides in also, and it's smaller, so I divided by 3 to get 245. This is not divisible by 3 but is divisible by 5, so I divided by 5 and got 49, which is divisible by 7.

PLEASE ANSWER QUICKLY Find the distance between points (4, 2) and (7, 2) on the coordinate
plane.

Answers

Answer:

3 units

Step-by-step explanation:

(4,2) (7,2)

Subtract 4 from 7 = 3

Subtract 2 from 2 = 0

This means that (7,2) is 3 units up from (4,2).

:) ur welcome

Answer:

Step-by-step explanation:

D=√(x2-x1)²+(y2-y1)²

D=√(7-4)²+(2-2)²

D=√(3)²+0

D=3²*½

D=3

At the 6th grade school dance, there are 132 boys, 89 girls, and 14 adults. What is the ratio of students to adults at the school dance?​

Answers

9514 1404 393

Answer:

  221 : 14

Step-by-step explanation:

The ratio is ...

  students : adults = (boys + girls) : adults = (132 +89) : 14 = 221 : 14

__

That's about 15.8 to 1.

Answer:

221:14

Step-by-step explanation: 132+89=221 (students) and 14 adults and the order is students to adults so 221:14

El arquitecto Gómez, dirige el proyecto de remodelación del parque municipal del distrito La Esperanza. La forma del parque está representada por la ecuación polar r(5-3sensθ)=16. El arquitecto planea construir un camino que une los extremos de la parte más ancha del terreno y necesita saber la distancia que existe entre los extremos (considerar que las medidas están en cientos de metros), además en el centro del camino colocará una pileta. Por ello, se requiere obtener las coordenadas de los extremos y del centro en coordenadas rectangulares. Para ayudar al arquitecto Gómez a lograr su objetivo, se deberá seguir la siguiente estrategia:
Pasar la ecuación polar a rectangular (en su forma ordinaria) (2 Puntos)
Hallar el centro, los vértices de la parte más ancha del terreno en la forma rectangular y determinar la distancia entre los vértices (considerar que las medidas están en cientos de metros), utilizando la ecuación cartesiana, hallada en a). (2 Puntos)
Graficar la cónica en el plano cartesiano ubicando las coordenadas de los vértices y del centro. (1 Punto)

Answers

Answer:

thank you for the point too mucheee

You: Your welcome

Joan has raised $306 by selling 34 equally priced boxes of chocolate for the team fund-raiser. Which of the following equations can be used to find the price, n, of each box of chocolate?

n ÷ 34 = 306
34n = 306
n − 34 = 306
n + 34 = 306

Answers

Answer:

34n=306

Step-by-step explanation:

Use inverse operation to find it, 306÷34= 9, check again 34(9)=306, so it's correct!

answer 34n=306 hope this helps

Can you help me figure out this question I’ve been stuck on this for 20 minutes

Answers

Step-by-step explanation:

[tex]\dfrac{2x^2+x-6}{x+x-6} = \dfrac{(2x-3)(x+2)}{2(x-3)}[/tex]

Suppose that all of the points on the circular dartboard shown are equally likely to be hit by a dart. If the radius of the shaded center circle is 1 and the radius of the entire dartboard is 4, what is the probability of throwing a dart and hitting the white part of the board? Round your answer to the nearest whole number.


6%


34%


67%


94%

Answers

Answer:

94%

Step-by-step explanation:

Consider a relation on the set of all states in the United States given by: two states are related if they have a border in common. Is it an equivalence relation

Answers

Answer:

Yes it is an equivalence relation

Explanation:

An equivalence relation is a binary relation between two values that are symmetric, transitive and reflexive. In other words, when we say a value x is equal(using "=") to a value y, there is an equivalence relation between them.

Example, given set {x, y, z} where ~ means equivalence:

x ~ y if y ~ z means symmetric

since x ~ y and y ~ z, then x ~ z means transitive

x ~ x means reflexive

Equivalence relations share a common attribute or attributes(example, a satisfying condition)

The above condition that two states are related from the set of all US states if they have a border in common satisfies the condition of equivalence listed hence it is an equivalence relation.

round 3,236 to the nearest hundred

Answers

Answer:

3,200

Step-by-step explanation:

3 is less than 5 so you round down to 3,200

3,200. You’re asked to the nearest hundred so you focus on 3 only. Since 3 is less than 5, it becomes 0. So 3,236 to the nearest hundred is 3,200.

i’ll give brainliest to the right answer

Answers

the answer is A. 0.0000805

Answer:

First one , 0.0000805

Step-by-step explanation:

With negative exponents the decimal is moved to the left the amount of the exponent. The spaces are filled with zeros.

With positive exponents the opposite occurs.  The decimal moves to the right.

An automatic machine inserts mixed vegetables into a plastic bag. Past experience revealed that some packages were underweight and some were overweight, but most of them had satisfactory weight.
Weight % of Total Underweight 2.5 Satisfactory 90.0 Overweight 7.5a) What is the probability of selecting and finding that all three bags are overweight?b) What is the probability of selecting and finding that all three bags are satisfactory?

Answers

Answer:

a) 0.000016 = 0.0016% probability of selecting and finding that all three bags are overweight.

b) 0.729 = 72.9% probability of selecting and finding that all three bags are satisfactory

Step-by-step explanation:

The condition of the bags in the sample is independent of the other bags, 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.

a) What is the probability of selecting and finding that all three bags are overweight?

2.5% are overweight, which means that [tex]p = 0.025[/tex]

3 bags means that [tex]n = 3[/tex]

This probability is P(X = 3). So

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

[tex]P(X = 3) = C_{3,3}.(0.025)^{3}.(0.975)^{0} = 0.000016[/tex]

0.000016 = 0.0016% probability of selecting and finding that all three bags are overweight.

b) What is the probability of selecting and finding that all three bags are satisfactory?

90% are satisfactory, which means that [tex]p = 0.9[/tex]

3 bags means that [tex]n = 3[/tex]

This probability is P(X = 3). So

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

[tex]P(X = 3) = C_{3,3}.(0.9)^{3}.(0.1)^{0} = 0.729[/tex]

0.729 = 72.9% probability of selecting and finding that all three bags are satisfactory

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