A 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 6.2 hours. How large a sample must be selected if he wants to be 99% confident of finding whether the true mean differs from the sample mean by 1.5 hours

Answers

Answer 1

Answer:

The Sample Size Need To be at least 114

Step-by-step explanation:

According to the Question,

Given, A 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 6.2 hours.

The Maximum Error(E) is given as 1.5 hours and the standard deviation(σ) is 6.2 hours.

Now, For 99% Confident the level of value α is 0.01.

α/2 = 0.01/2 ⇒ 0.005

Thus, From The table, We get that the value of [tex]Z_{alpha/2}[/tex] is 2.58.

Hence, the sample size n can be found as

n = {[tex]\frac{(Z_{alpha/2} * Standard Deviation)}{E}[/tex]}²

n = {2.58 × 6.2}² / 1.5²

n = 113.72 .

So, The Sample Size Need To be at least 114.


Related Questions

What is the value of “a” in the function equation?

Answers

Answer:     the value of A is 2

Step-by-step explanation:

QUESTION 6 The scale on a map is given as 1 : 320,000. If the distance between the top of the two mountains on the map is 6.8cm, what is the actual distance in kilometres between the two tops of the mountain. ? show working out to prove answer.​

Answers

Answer:

The actual distance is of 21.76 kilometers.

Step-by-step explanation:

Scale problems are solved by proportions, using a rule of three.

The scale on a map is given as 1 : 320,000

This means that each unit on the map represents 320,000 units of distance.

Distance between the top of the two mountains on the map is 6.8cm

Then

1 cm - 320,000 cm

6.8 cm - x

Applying cross multiplication:

[tex]x = 6.8*320000 = 2176000[/tex]

Distance in kilometers

To convert from centimeters to kilometers, we divide by 100000. So

2176000/100000 = 21.76

The actual distance is of 21.76 kilometers.

Please I need help in finding the diameter

Answers

i think its 10 im not sure tho

Answer:

20

Step-by-step explanation:

diameter=√(12²+16²)=√[4²(3²+4²)]=4√(9+16)=4√25=4×5=20

Which statement regarding the diagram is true?

mMKL+mMLK=mJKM mKML+mMLK=mJKM mMKL+mMLK=180 mJKM+mMLK=180

Answers

Answer:

mKML+mMLK=mJKM

Step-by-step explanation:

A triangle is a polygon with three sides and three angles. Types of triangles are scalene, acute, obtuse, equilateral, isosceles, and right triangle.

As shown in the diagram, polygon MLK is a triangle. The sum of angles in a triangle is equal to 180°, hence:

m∠MLK + m∠KML + m∠MKL = 180° (sum of angles in a triangle).

m∠MKL = 180 -  (m∠MLK + m∠KML)      (1)

Also along line JL, the sum of angles on one side of a straight line is 180°, therefore:

m∠JKM + m∠MKL = 180° (sum of angles in a straight line)

m∠JKM + m∠MKL = 180°                (2)

From equations 1 and 2, equating give:

m∠JKM + [180 -  (m∠MLK + m∠KML)) =  180

m∠JKM + 180 - m∠MLK - m∠KML =  180

m∠JKM = m∠MLK + m∠KML

I need help please :)

Answers

Answer : C) 72°

The angle measure we’re looking for is an inscribed angle, this means it lies on the arc and it’s going to be exactly one half the value of the arc directly across from it (arc XZ).

To find the value of XZ you add 108 + 108 because the arcs XY and YZ have the same value. This = 216.

We then subtract 360 - 216 to find arc XZ, because 360° is the full measure of a circle.

360 - 216 = 144

Then divide by 2

144/2 = 72.

Someone please help I have 40 mins for this test !

Answers

Answer:

It would be Linear

Step-by-step explanation:

Answer:

i think its quadratic because the graph isnt straight and has different slopes between the x,y.

Step-by-step explanation:

Solve the equation and check the result
3(2y-8)-y=9

Answers

Answer:

y = 33/5

Step-by-step explanation:

Distribute

3(2y-8)-y = 9

6y - 24 - y

5y - 24 = 9

Add 24 to both sides

5y = 9 + 24

5y = 33

y = 33/5

simplify -5-√-44

i have no idea

Answers

Answer:

Undefined

Step-by-step explanation:

The square root of a negative number does not exist in the set of real numbers so it would be Undefined

Let X denote the number of bars of service on your cell phone whenever you are at an intersection with the following probabilities.

x 0 1 2 3 4 5
P(X=x) 0.1 0.15 0.25 0.25 0.15 0.1

Determine the following probabilities
a. Two or three bars
b. At least one bar
c. Fewer than two bars
d. More than three bars

Answers

Answer:

a. [tex]P(2 \leq X \leq 3) = 0.5[/tex]

b. [tex]P(X \geq 1) = 0.9[/tex]

c. [tex]P(X < 2) = 0.25[/tex]

d. [tex]P(X > 3) = 0.25[/tex]

Step-by-step explanation:

We are given the following distribution:

[tex]P(X = 0) = 0.1[/tex]

[tex]P(X = 1) = 0.15[/tex]

[tex]P(X = 2) = 0.25[/tex]

[tex]P(X = 3) = 0.25[/tex]

[tex]P(X = 4) = 0.15[/tex]

[tex]P(X = 5) = 0.1[/tex]

a. Two or three bars

[tex]P(2 \leq X \leq 3) = P(X = 2) + P(X = 3) = 0.25 + 0.25 = 0.5[/tex]

Thus:

[tex]P(2 \leq X \leq 3) = 0.5[/tex]

b. At least one bar

[tex]P(X \geq 1) = 1 - P(X = 0) = 1 - 0.1 = 0.9[/tex]

Thus:

[tex]P(X \geq 1) = 0.9[/tex]

c. Fewer than two bars

[tex]P(X < 2) = P(X = 0) + P(X = 1) = 0.1 + 0.15 = 0.25[/tex]

Thus:

[tex]P(X < 2) = 0.25[/tex]

d. More than three bars

[tex]P(X > 3) = P(X = 4) + P(X = 5) = 0.15 + 0.1 = 0.25[/tex]

Thus:

[tex]P(X > 3) = 0.25[/tex]

4( x + 2) + 6x in the simplest form

Answers

Answer:

10x+8

Step-by-step explanation:

4( x + 2) + 6x

Distribute

4x+8 +6x

Combine like terms

10x+8

Answer:

10x+8

Step-by-step explanation:

4x+8+6x

(4x+6x)+8

10x+8

A bicycle wheel with radius 26" rotates through an arc that measures 80°. What is the length of the arc of the tire that touched the ground? 5.78 inches 11.56 inches 2.88 inches

Answers

Answer:

104/4 pi

Step-by-step explanation:

Answer: The circumference of a circle is:

Radius = r, Diameter = d, C = Circumference

C=2πr (as 2r=d)

C=πd

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

If the radius of the circle is 26" then its diameter must be 52".

This means that the bicycle wheel has a circumference of 52π".

I'm going to divide 52π" into 360 parts (because a circle is made up of 360 degrees). I'll then multiply this value by 80 to give you an answer.

Determine the list of numbers 14, 18 and 33 can be measured of the sides of a triangle if so clarify the triangle as a cute right or obtuse

Answers

9514 1404 393

Answer:

  no

Step-by-step explanation:

The measures 14, 18, 33 cannot correspond to the sides of a triangle. The two short sides total 32 in length, so cannot meet up with the ends of the side whose length is 33. A triangle cannot be formed.

Find the surface area of a square pyramid with side length 4 and slant height 5.

Answers

Answer:

56

Step-by-step explanation:

the surface area = (4×4) + (4×½×4×5)

= 16 + 40

= 56

What is an inscribed polygon is being constructed

Answers

A square

Step-by-step explanation:

because there're only 2 circles being create whereas with an equilateral

Answer:

A square

Step-by-step explanation:

Make x the subject of the formula p = x + a b

Answers

Answer:

Step-by-step explanation:

x + ab = p

x = p - ab

someone pls help its due soon

Answers

9514 1404 393

Answer:

  II only

Step-by-step explanation:

You can simplify the inequality like this:

  3 -8 > 8 -8 + 5x . . . . . . . . subtract 8 from both sides

  -5 > 5x . . . . . . . . . . . . . simplify

  -5/5 > (5x)/5 . . . . . . . divide both sides by 5

  -1 > x . . . . . . . . . . . . simplify

I find this easier to compare to a numbers on a number line if the inequality symbol points to the left. (This is a personal preference. YMMV)

  x < -1

Now, we can see that only numbers to the left of -1 on the number line will be suitable values for x. Of those listed, only -9 is a solution.

  II only

how do i solve this ?

Answers

Answer:

[tex]2\sqrt{2}[/tex]

Step-by-step explanation:

The given triangle is an isosceles triangle. However, one can see that it has a right angle (indicated by the box around the angle). Thus the triangle is a (45 - 45 - 90) triangle. A (45- 45 - 90) triangle is the only right isosceles triangle. One of the properties of a right isosceles triangle is that its sides follow the following ratio,

[tex]a;a;a\sqrt{2}[/tex]

Where (a) represents the legs of the right triangle, the sides that are adjacent to the right angle, in this case, the congruent sides. ([tex]a\sqrt{2}[/tex]) is the hypotenuse, the side opposite the right angle.

It is given that the hypotenuse is equal to (4), one is asked to find the length of the legs. To do so, divide the hypotenuse by ([tex]\sqrt{2}[/tex]) to find the legs. One can do this because the triangle is a (45 - 45 - 90) triangle, thus it must follow the ratio of the sides.

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

Rationalize the denominator,

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

If the original quantity is 14 and new quantity is 35 what is the percent change

Answers

Answer:

150%

Step-by-step explanation:

given:

original quantity = 14

new quantity = 35

increased quantity = 35 - 14

=21

percent change = increased quantity /original quentity * 100%

=21/14 *100%

=21100/14 %

=150 %

Simplify each expression by writing the expression without absolute value bars

Answers

Answer:

-1

Step-by-step explanation:

When b<4

|b-4|  is negative

|b-4|  = - ( b-4)

- (b-4) / ( b-4) =

Factoring out (b-4)

-1

0.0543 nearest whole number

Answers

0.0543 nearest whole number is 1 i think

Answer:

0

Step-by-step explanation:

Ignore the next 2 numbers after 0.05. To the nearest whole number, round 0.05 to the nearest tenth, 0.1. Then round that to the nearest whole number, 0, which is your answer.

NO LINKS OR ELSE YOU'LL BE REPORTED! Only answer if you're very good at Math.

Ms. Nellies has 2 1/2 pints of vinegar for her students to use in a science experiment.Each group of students needs 3/8 pint of vinegar.Trey draws the number line model and writes the equation below to help Ms. Nellies figure out how many 3/8-pint serving of vinegar she has.Are Trey's number line model and equation correct?

Trey's number line is _______ because it represents the expression _________.The correct equation is _______.Ms. Nellies has enough vinegar for _________ groups of students.

1st blank box: correct or incorrect

2nd blank box: 2 1/2 x 3/4,2 1/2 ÷ 3/4,2 1/2 x 3/8,or 2 1/2 ÷ 3/8.

3rd blank box: 2 1/2 ÷ 3/8= 6 2/3,2 1/2 ÷ 3/8 = 3 1/3,2 1/2 x 3/8 = 2 3/16, or 2 1/2 ÷ 3/8 = 15/16

4th blank box: 2,6,3,or 0


Answers

Answers:

Trey's number line is incorrect because it represents the expression 2 1/2 ÷ 3/4.

The correct equation is 2 1/2 ÷ 3/8 = 6 2/3.

Ms. Nellies has enough vinegar for 6 groups of students.

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

Explanation:

Trey has the right idea, but made a mistake on how the tickmarks are set up. Focus on the interval from 0 to 1. This section is cut into 4 equal pieces. So each tickmark represents 1/4 of a unit.

Going 3 tickmarks across means 3/4 of a unit is represented. Since each larger arc represents 3/4 of a unit, this means we're dividing the 2 & 1/2 over 3/4 instead of 3/8

That's why Trey's model represents 2 1/2 ÷ 3/4

The value 3 & 1/3 at the end is correct. Visually we see 3 whole jumps plus an extra 1/3 of a jump to arrive at 2 & 1/2. But again, Trey didn't cut the number line up in the right way, so it doesn't matter that he arrived at the correct result of 3 & 1/3 since his initial setup is faulty.

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

See the diagram below to see what Trey should have drawn. Notice each tickmark represents 1/8 instead of 1/4. Each large blue arc jump represents 3/8 of a unit. We have exactly 6 of these blue arcs plus 2 additional smaller arcs that are 1/3 of the blue arc. So that accounts for the 1/3+1/3 = 2/3 portion.

Overall, we would say that the equation is 2 1/2 ÷ 3/8 = 6 2/3

If you're curious why that equation works, check out the steps below

[tex]2 \frac{1}{2} \div \frac{3}{8} = \frac{5}{2} \div \frac{3}{8}\\\\2 \frac{1}{2} \div \frac{3}{8} = \frac{5}{2} \times \frac{8}{3}\\\\2 \frac{1}{2} \div \frac{3}{8} = \frac{5*8}{2*3}\\\\2 \frac{1}{2} \div \frac{3}{8} = \frac{40}{6}\\\\2 \frac{1}{2} \div \frac{3}{8} = \frac{20}{3}\\\\2 \frac{1}{2} \div \frac{3}{8} = \frac{18+2}{3}\\\\2 \frac{1}{2} \div \frac{3}{8} = \frac{18}{3}+\frac{2}{3}\\\\2 \frac{1}{2} \div \frac{3}{8} = 6+\frac{2}{3}\\\\2 \frac{1}{2} \div \frac{3}{8} = 6\frac{2}{3}\\\\[/tex]

So again, the equation is 2 1/2 ÷ 3/8 = 6 2/3

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

What does this all mean? Well it means the teacher can break up the vinegar into 6 whole parts plus an additional 2/3 of a part.

In other words, 6 groups will get 3/8 of a pint each. The leftover part 2/3 isn't enough to form that 7th group. Notice in the diagram below, we have 2/8 = 1/4 of a pint which is smaller than 3/8 of a pint.

1/4 = 0.25

3/8 = 0.375

So this is another way to see that the leftovers isn't enough to form a 7th group.

Therefore, she has enough vinegar for 6 groups

Find the area of the triangle, WILL GIVE BRAINLIEST

Answers

Answer:

10 cm^2

Step-by-step explanation:

area= 1/2 b*h

1/2 (5) (4)

= 1/2 (20)

=10

area= 10cm^2

Answer:

a = 10cm²

Step-by-step explanation:

a = (1/2)bh

a = (1/2)(5)(4)

a = 10cm²

PLS HELP
Which is a solution for the inequality -6x – 5 <-23 ?
(1) O
(2) 2
(3) -2
(4) 5

Answers

It would be x is greater then 3 so anything above 3 which would be 5
So the answer is
(4) 5

can someone please tell me the answer .

Answers

Answer:

Step-by-step explanation:

Answer:

the last one

Step-by-step explanation:

congruent means they are the same and all sides of a square are the same size.

this................................................................................................

Answers

Answer:

5

Step-by-step explanation:

3-(-2)

the two negative signs cancel out and it turns into

3 + 2

3 + 2 = 5

Answer:

5

Step-by-step explanation:

minus * minus = plus

3-(-2) = 3 + 2 = 5

fill in the blanks
864+2006=--------+864

5351 +(574+799)= 574+(5351+_____)​

Answers

Answer:

2006

799

Step-by-step explanation:

Given the expression:

The right hand side of the sun must be equal to the left hand side ;

Therefore ;

864+2006=--------+864

The sum of 864 and 2006 must be equal to the right hand side sum ; hence

864+2006= 2006 +864

Similarly, the left hand side and right havd side must also be equal here ;

5351 + 574 + 799 = 574 + 5351 + 799

Hence, the missing value is 799

At a sale this week, a suit is being sold for $235.60. This is a 62% discount from the original price.
What is the original price?

Answers

Answer:

$620

Step-by-step explanation:

(1-62%)X=235.6

X=235.6/38%

X=620

The original price is $620

Triangle ABC has vertices A (-2, 2), B (2, 4) and C (3, -1).  What are the coordinates of A' after a dilation by a scale factor of 2.5?​

Answers

Answer:

A’(-5,5)

Step-by-step explanation:

x’ = 2.5 * -2 = -5

y‘ = 2.5  * 2 = 5


i need help finding the answer with step by step

Answers

Answer:

x= -1

Step-by-step explanation:

if

f(x) = -x-3

and

f(x) = -2

than

-x-3 = -2; add 3 to both sides

-x-3+3 = -2+3

-x = 1 ; multiply both sides by -1

x= -1

NEED HELP ASAP PLEASE
Assume that a three-month CD purchased for $3000 pays simple interest at an annual rate of 10%. How much total interest does it earn?

$ ____

What is the balance at maturity? ______

Answers

Answers:

interest = $75balance at maturity = $3075

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

Explanation:

The simple interest formula is

i = p*r*t

where in this case,

p = 3000 = principal (amount deposited)r = 0.10 = annual interest rate in decimal formt = 3/12 = 0.25 = number of years

So,

i = p*r*t

i = 3000*0.10*0.25

i = 75 is the amount of interest earned

This adds onto the initial deposit to get the final balance when the CD matures (ie when you're able to withdraw the money without penalties)

The balance at maturity is p+i = 3000+75 = 3075 dollars

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

In short, you deposit $3000 into the CD and have to wait 3 months for the amount to update to $3075.

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