The effectiveness of two types of textbook is compared. A class of 30 students is randomly divided into two groups. One group uses digital textbooks and the other group uses paper textbooks. A summary of their test scores at the end of the session is given below. Digital Textbook: Paper Textbook: Construct a 90% confidence interval for the difference in scores between the two groups assuming underlying normal distributions with equal variance. Find the lower bound of the confidence interval (round off to first decimal place).

Answers

Answer 1

Answer:

- 18.377

Step-by-step explanation:

n1 = 17 ; xbar1 = 78.4 ; s1² = 90.3

n2 = 13 ; x2bar = 92 ; s2² = 107.8

Confidence interval :

(x1 - x2) ± Tcritical * sqrt[(sp²/n1 + sp²/n2)]

Pooled variance = Sp² = (df1*s1² + df2*s2²) ÷ (n1 + n2 - 2)

df = n - 1

Sp² = (16*90.3 + 12*107.8) / 28

Sp² = 97.8

Tcritical, 90%, df = n1 + n2 - 2 = 28 (1 - tail)

Tcritical = 1.313

(78.4-92)±1.313*sqrt[(sp²/n1 + sp²/n2)]

Margin of Error = Tcritical * sqrt[(sp²/n1 + sp²/n2)] Margin of Error = (1.313 * √(97.8/17 + 97.8/13)) = 4.7771473

Lower boundary :

(78.4-92) - 4.7771473

-13.6 - 4.7771473

= −18.3771473

= - 18.377


Related Questions

A principal of $3600 is invested at 3.5% interest, compounded annually. How much will the investment be worth after 12 years? Use the calculator provided and round your answer to the nearest dollar. X S​

Answers

Answer:

$5043

Step-by-step explanation:

To find the value of the investment after 12 years, you can use the following formula:

A = P * (1 + r/n)^(nt)

Where:

A = final amount

P = principal

r = interest rate

n = number of times the interest is compounded per year

t = number of years

Plugging in the values from the problem, we get:

A = 3600 * (1 + 3.5/100)^(1*12)

Solving this equation, we get:

A = $5043.33

So, after 12 years, the investment will be worth $5043.33.

A movie theater sells popcorn in bags that open to form similar prisms, as shown. The large bag has a volume of 576 cubic inches. The small bag is 12 in tall and the large bag is 16 in tall. What is the volume of the small bag?

Answers

Can’t be determined
Can’t be determined

PS lies on the perpendicular bisector of QR. Select all the statements about the figure that must be true.

Answers

Of the given statements, only the option number {5} and {6} are true.

What is perpendicular bisector?

The perpendicular bisectors of a triangle are lines passing through the midpoint of each side which are perpendicular to the given side. A triangle's three perpendicular bisectors meet at a point. known as the circumcenter, which is also the center of the triangle's circumcircle.

Given is a triangle as shown in the image.

Since PS is the perpendicular bisector of QR, we can write -

QS = SR

6n + 3 = 4n + 11

2n = 8

n = 4

QR = QS + SR

QR = 6n + 3 + 4n + 11

QR = 10n + 14

QR = 10 x 4 + 14

QR = 54

and

SR = 4n + 11

SR = 16 + 11

SR = 27

Therefore, of the given statements, only the option number {5} and {6} are true.

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- Joy and John MacAllister have agreed to purchase a house for $79,900. First
National Savings & Loan is willing to lend the money at 7.5 percent for
25 years, provided the MacAllisters can make a $19,900 down payment. The
total closing cost is 3.5 percent of the amount of the mortgage. What is their
total closing cost?

Answers

Answer:

Step-by-step explanation‎:

5 in. 3 8 in. What is the volume, in cubic inches, of the prism? cubic inches​

Answers

Answer:

70in^3

Step-by-step explanation:

Ok so the the formula for volume for a cube is V= L x W x H

so if the dimensions are 5in by 3in by 8in, the volume of the cube is 5x8x3 = 70 inches^3

Two car dealerships pay their employees a monthly salary plus a commission on cars that they sell.

Answers

The person who is right on the dealership that pays a higher commission, is Tyson because Dealership A pays the higher commission.

How to find the commission paid ?

The commission paid on Dealership A cars can be found by the formula :

= ( Monthly income for 4 cars - Monthly income for 1 car ) / Difference in number of cars

= ( 3, 850 - 1, 900 ) / ( 4 - 1 )

= $ 650

The commission paid on Dealership B cars would be:

= ( Monthly income for 4 cars - Monthly income for 1 car ) / Difference in number of cars

= ( 3, 500 - 2, 000 ) / ( 4 - 1 )

= 1, 500 / 3

= $ 500

Dealership A pays the higher commission.

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Debby deposits 25% if the money that she earns each week in a savibgs account if debby earns $72 each week, how much money will she deposit next week

Answers

$18 is the answer

($72 x 25%)

What is the probability of tossing a coin and getting heads three times in a row?

What is the chance that the next toss will be heads? What is the chance that the next toss will be tails?

Answers

The probability of tossing 3 heads in a row is P = 0.125, and after that, because the events are independent, the probability of getting heads (or tails) still is p = 0.5

How to find the probability?

Assuming that we have a fair coin, we assume that both outcomes have the same probability, so:

P(tails) = 0.5

P(heads) = 0.5

Then the probability of getting heads 3 times in a row, is the product of the probability of getting heads 3 times, this will be:

P(3 heads) = 0.5*0.5*0.5

P(3 heads) = 0.5^3

P(3 heads) =  0.125

Now, after this point, what is the probability of getting heads or tails?

Remember that each toss of the coin is independent of the previous one, so the probability of getting tails still is 0,5, and the same for the probability of getting heads.

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HELP MEEEEEE PLEASESEE PLEASE

Answers

Answer:

240 grams

Step-by-step explanation:

720-480=240

Answer:

240

Step-by-step explanation:

subtraction

720-480

I thought of a number, added 26 to it, and then divided the result by 20. What is my number?

Answers

Answer:

12?

Step-by-step explanation:

A cylindrical paint can has a diameter of 12 centimeters and
height of 16 centimeters. Which is closest to the volume of
the paint can in cubic centimeters?

Answers

Answer:

Step-by-step explanation:

you could find the area of the circle ,  then multiply that by the height

area of circle = [tex]\pi[/tex][tex]r^{2}[/tex]

[tex]\pi[/tex][tex]6^{2}[/tex]=113.0973355

16*113.0973355=1809.5573

The volume of the paint can in cubic centimeters 1808.64 cm³.

what is Volume?

The amount of space occupied by a three-dimensional figure as measured in cubic units.

given: radius= 6cm and height= 16 cm

Volume of cylinder= πr²h

                               = 3.14*6*6*16

                               = 1808.64 cm³

Thus, the volume of the paint can in cubic centimeters 1808.64 cm³.

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If f(x) = 2x4 - 3x + 3, then what is the remainder when f(x) is divided by x - 1?

Answers

The remainder on dividing 2x⁴-3x+3 by x-1 is 2

What are functions?

Function, in mathematics, is an expression, rule, or law that defines a relationship between one variable (the independent variable) and another variable (the dependent variable).

Given here: 2x⁴-3x+3 by x-1

The remainder theorem states that when a polynomial p(x) is divided by (x - a), then the remainder = f(a)

∴ The remainder would is f(1) = 2×1-3+3

                                                 =2

Hence, The remainder on dividing 2x⁴-3x+3 by x-1 is 2

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Choose the mathematical sentence that most accurately expresses the
information in the problem, and would be most helpful in solving it.
There are 25 milligrams of sodium per serving in a bag of potato chips. In
that bag there are 5 servings. How many milligrams of sodium are there in the
whole bag?
A. S+5 = 25
B. 5 : s= 25
C. S-5 = 25
D. s = 5(25)
O E. S : 5 = 25
O F. S = 25+ 5

Answers

Answer:

[tex]s = 5 * 25[/tex]

Step-by-step explanation:

Given

[tex]Servings = 5[/tex]

[tex]Sodium/Serving = 25mg[/tex]

Required

The number of sodium mg in the bag

This is calculated as:

[tex]s = Servings * Sodium/Serving[/tex]

[tex]s = 5 * 25[/tex]

Hence: (D) is correct

There are 5 yellow golf balls, 3 red golf balls, and 10 white golf balls in a bag. What are the odds of randomly choosing a yellow golf ball?

Answers

Answer:

5/18

Step-by-step explanation:

Answer:

2

Step-by-step explanation:

1+1=2

Solve for the value of c (2c-4) (5c+3)

Answers

Is this correct ☑️☑️✔️

Answer:

its 13

Step-by-step explanation:

summarize how you can find the slope of a perpendicular line.

Answers

Finding the slope of a perpendicular line is fairly simple…

Let’s say we have the line given in slope-intercept form (y=mx+b), y=3x+1.

We know looking at this equation that the slope of the line is 3. To find a slope that is perpendicular you need to find it’s opposite reciprocal. In the case of 3, it’s opposite would be from + to -, so -3. The reciprocal would flip the number into a fraction -3 => -1/3. So the line perpendicular would have a slope of -1/3.


Steps:
1. Determine the slope of the line

2. Switch from a positive to a negative or a negative to a positive

3. Find the reciprocal (2/5 => 5/2, 1/4 => 4)

Since "slope" tells us the angle of the line being graphed, the word "slope" is commonly used in mathematics.

Planar geometry states that all lines have slopes. Any slope can be calculated by comparing it to another line, usually the x-axis. A line's slope, or angle, in relation to that x-axis value is how steep it is.

In mathematics, slope is the proportion of the change in the y value to the change in the x value.

Two perpendicular lines have a slope such that the reciprocal of the negative slope of one line equals the slope of the other. The slope of perpendicular lines is -1 as a result.

The relationship between the slopes of parallel lines can be demonstrated using the formula m1.m2 = -1, if the slopes of the two perpendicular lines are m1, m2.

Like a fraction, a slope works by favoring the rise, up-and-down movement, over-the-run, or side-to-side movement. If a line rose up one unit for every rightward unit traveled, the slope would be a positive one.

To know more about "slope" here.

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Given the number 254, 476, 951
What number is in the TEN THOUSAND's SPOT?

Answers

Step-by-step explanation: 1 is in the ten thousand places and has a place value of 10,000. 3 is in the thousand's place and has a place value of 3,000. 5 is in the hundreds and has a place value of 500.

It takes 3 eggs to make a cake .how many cakes can you make with 37 eggs

Answers

Answer:

12 cakes

Step-by-step explanation:

37 / 3 = 12.33333

A house 20 meters long and 15 meters wide is surrounded by a verandah of uniform width of 3 meters. Find the cost of the flooring the verandah at RS 200 per square meter

Answers

Answer:

49200 rs. so the cost of flooring =246*200=49200 rs

Step-by-step explanation:

Solution :

we measure the area of veranda by taking width in addition of length and breadth- house area

it means

area of veranda =outer rectangle-inner rectangle

⇒area= (20+3+3)*(15+3+3)-20*15

⇒area=26*21-300

⇒area= 546-300

⇒area=246 m²

Hence , the cost of flooring =246*200=49200 rs.

AB=25 , BD=4, Solve for the radius?
Please help!!!!!

Answers

9514 1404 393

Answer:

  r = 14.5

Step-by-step explanation:

AD is the perpendicular bisector of chord EC, so is the diameter of the circle. The radius is half the diameter.

  r = AD/2 = (AB +BD)/2 = (25 +4)/2 = 29/2

  r = 14.5

__

Segments BE and BC are 10 = √(25·4)

i dont understand this help

Answers

laucs ori nisiquiera estoy en universidad estoy en eseyo pe

if someone takes your food is it still sharing ​

Answers

Yes, it is not sharing by choice but you are technically still giving it to the person.

Answer:

not unless you want them to have it :)

Step-by-step explanation:

I need help pls answer

Answers

Increase=5%/100% x $12 =0.60
$12.00 + $0.60=$12.60

I need help with this question please help me with this

Answers

By basic algebra, the part to be cut is equal to 17/45. When the numerator exceeds or is equal to the denominator, the fraction is said to be improper. 5/2 and 8/5, for instance, are improper fractions. Each fraction has two components.

In math, what is a fraction?

An element of a whole is a fraction. The number is represented mathematically as a quotient, where the numerator and denominator are divided. Both are integers in a simple fraction. A fraction appears in the numerator or denominator of a complex fraction. The numerator of a proper fraction is less than the denominator.

Let x part is cut to shorten

then,

[tex]\frac{3}{2}-x=\frac{2}{9}\\\\x=\frac{3}{5} -\frac{2}{9} \\\\x=\frac{17}{45}[/tex]

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Determine a system of linear equations that represents the problem. Be sure to explain how you created the equations.

Answers

Answer:

a-

3x+3y=11.25

4x+2y=10

You find a mutual fund that offers approximately 6% APR compounded
monthly. How much will you need to invest each month for the next year in
order to have $1000?

Answers

Answer:

$81.06

A P E X :)

need help solving this problem please ​

Answers

Step-by-step explanation:

[tex] \cos( \frac{ \alpha }{2} ) = \sqrt{ \frac{1 - \cos( \alpha ) }{2} } \\ = \sqrt{ \frac{1 - ( - \frac{15}{17}) }{2} } \\ = \sqrt{ \frac{32}{34} } [/tex]

speeeeeeeedddddddddddddddddddddddddddddddd

Answers

Answer:

I would be ...

75/8

multiple 9 by 8 and then add 3

Hope this helps!

Step-by-step explanation:

;)

Answer:

75/8!

Step-by-step explanation:

HELPPP MEE THANK U, 20 POINTS!~

Answers

Answer:

B

Step-by-step explanation:

The second box plot starts later then the first one on the number line.

-5(6x+3y-1)
Simplify

Answers

Answer:

-30x+15y+5 is the simplified answer

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