A usability test was conducted to evaluate the design of a store website. The times to complete a certain task were recorded for a sample of 48 users. The sample mean time was 70 seconds with a 95% margin of error of 10 seconds. In other words, researchers estimated with 95% confidence that the mean time to complete the task was between 60 and 80 seconds for all website users. Only one of the following statements is true. Select the correct statement.
1. the probability that the mean time μ will fall between 60 and 80 is 0.95.
2. If many samples are collected from the same population, about 95% of the samples will produce confidence intervals that contain the population mean μ.
3. If a second sample from the same population is selected and a 95% confidence interval is constructed, the new confidence interval will be the same as the 95% C.I. defined in the first study.
4. If the study is repeated, and a new 95% confidence interval is computed, there is 95% chance that the new interval contains the sample mean value >= 40 seconds.

Answers

Answer 1

Answer:

2. If many samples are collected from the same population, about 95% of the samples will produce confidence intervals that contain the population mean μ.

Step-by-step explanation:

x% confidence interval:

A confidence interval is built from a sample, has bounds a and b, and has a confidence level of x%. It means that we are x% confident that the population mean is between a and b.

So the correct option is given by:

Option 2, as we will be 95% sure that the population mean will be in the interval, which can be interpreted that from many samples, about 95% will contain the population mean.


Related Questions

To stay in a hotel it costs $104 each night (n) plus a $15 fee for parking. Think of the linear function that demonstrates the total cost (C) of staying in the hotel in terms of the number of nights (n) stayed. whats the initial value ? ​

Answers

Answer:

the equation is:    (104 * x) + 15 = y     i believe

Step-by-step explanation:

104 OF THE NUMBER of nights so times x because you dont know the number

and + 15 because of the fee

Which of the following is NOT a rate?
A
6 meters per second
O
B. 15 dollars per hour
C. 3 seconds per second
D. 2 dollars per pound

Answers

Answer:

c

Step-by-step explanation:

now are you going to get 3 seconds out of a second

Answer:

C

Step-by-step explanation:

C dosen't even make sence, so I think it is C.

A triangular pyramid has a base area of 74 square inches and a height of 9 inches. Which is closest to the volume of the pyramid?
a 351 cubic inches
b 702 cubic inches
c 224 cubic inches
d 234 cubic inches

Answers

Answer:

702

Step-by-step explanation:

because 74 x 9 = 666 and 702 is close

17
Write the integers that are closest to the number in the middle to complete the statement.

Answers

I think it’s 15! Hope this helpsssssss

Sam plans to use two flags on his float for the parade. Each flag is a right triangle and the triangles are similar.What is the width, x, of the larger flag in feet? halp please!!! 100 POINTS

Answers

Answer:

6.25 ft

Step-by-step explanation:

The smaller flag width is 5. And the larger flag is not that big in size. So the close answer is 6.25

Answer:

6.25ft

Step-by-step explanation:

Please explain in words.

Answers

Answer:

Negative

Step-by-step explanation:

The following expression will be negative. This is because, the fraction in x is a negative fraction. The fraction in y is a positive fraction. The expression is    x * y, so if you were to multiply the two it would be negative. This is because a negative multiplied by a positive will be equal to a negative.

Hope this helps!!

-Ketifa

(Can I get brainliest?)

need help with thiss guys!!!

Answers

I would choose D for that question

A chemist wishes to mix a solution that is 12% acid. She has on hand 6 liters of a 4% acid solution and wishes to add some 16% acid solution to obtain the desired
12% acid solution. How much 16% acid solution should she add?
Complete the table.
Liters of
Solution
Percent Acid Liters of
(as a decimal) Pure Acid
0.04
6
Х
0.16
0.12

Answers

Answer:

25 liters of the 16% solution should be added.

Step-by-step explanation:

pure acid amount + pure acid amount = total pure acid amount

0.02*10          + 0.16*x           = 0.12*(10+x)     <<<---=== it is your balance equation;  x is the amount (in liters) of the 16% solution.

0.02*10 + 0.16x = 0.12*10 + 0.12*x

0.16*x - 0.12*x = 0.12*10 - 0.02*10

(0.16 - 0.12)*x = 0.12*10 - 0.02*10

x = %280.12%2A10-0.02%2A10%29%2F%280.16-0.12%29 = 25.

Answer.  25 liters of the 16% solution should be added.

Check.   %280.02%2A10+%2B+0.16%2A25%29%2F%2810+%2B+25%29 = 0.12 = 12% of concentration of the final mixture.   ! Correct !

What is the conjugate of (x2-6)?

Answers

Answer:

2(x - 3)

Step-by-step explanation:

Need help asap!!!
Convert to exponential form

Answers

Answer:

B

Step-by-step explanation:

Lia cut a long piece of into 2 pieces. One pieces of the string is 24 inches long, and the other piece of the string is 12 inches long. How many feet long was the piece of string before lia cut it?​

Answers

Answer:

24+12=36you find the total length

Answer:

3 feet

Step-by-step explanation:

How can you write and solve an addition or subtraction equation?

Answers

Answer:

What equation...................wait nvm


15 * 3/5


14. Will the product be greater than 15?

Answers

Answer:

No

Step-by-step explanation:

When you divide by a fraction or a decimal you are essentially multiplying that by something lesser than one and so the Calculator, if you are using a Calculator to solve this will, see multiplying something by a decimal or a fraction as a division and vice versa.

Please help!
Given the figure is a square, find x, y and z

Answers

Answer:

Step-by-step explanation:

Did u find it? Because I can’t figure it out euther

What is 4(3+x) and how do I solve it

Answers

Answer:

12 + 4x

Step-by-step explanation:

To solve this you would have to use the distributive property.

The problem would basically go like this.

4 (3+x)

(Distribute)

(4x3) (4 x X)

4x3 = 12, 4 x x = 4x

So the answer would be 12 +4x

Hope this helps :)

Answer:

12+4x

Step-by-step explanation:

4(3+x)

1️⃣Expand by distributing terms.

4*3+4x

2️⃣Simplify 4*3 to 12

12+4x

Answer: 12+4x

Done ✔

15 points really need the right answer :(

Answers

Answer:

-4x^9

Step-by-step explanation:

How to do 264 in Expanded form

Answers

Answer:

200+60+4

Step-by-step explanation:

200+60+4=264

A square has vertices at the points A(-4,-4), B(-5,-4), C(-5,-3), and D(-4,-3). What is the area of this square? A. 1 square unit B. 4 square units C. 9 square units D. 2 square units

Answers

Answer:

Step-by-step explanation:

The length of AB = 1 unit.

area of square = 1² unit² = 1 square unit.

Answer:it is 1

Step-by-step explanation:

Determine the number of x-intercepts that appear on a graph of eac
f(x) = (x + 1)(x - 3)(x - 4)

Answers

Check the photo to get the answer

Jane has 6 more than half the number of pairs of shoes that Mercedes has. Jane has j pairs of shoes, and Mercedes has m pairs of shoes. Write an equation that shows the relationship between j and m.

Answers

The correct equation is j= 1/2m +6


A__ function is a function in the form f(x) = ax? + bx+c, where a, b, and care real
numbers and a 70, that will graph as a parabola.

is it

a) quadratic
b) first
c) parabolic
d) second

Answers

The answer is quadratic

Represent 42 divided by 6 = 7 using subtraction

Answers

Answer:

42 - 6 - 6 - 6 - 6 - 6 - 6 - 6 = 0

or

42 - 7 - 7 - 7 - 7 - 7 - 7 = 0

Combine like terms
x + 10x-30= -8

Answers

Answer: x=2

Isolate the variable by dividing each side by the factors that don't contain variables.

Write an expression for the sequence of operations described below.
10 plus the quotient of 8 and u
Do not simplify any part of the expression.

Answers

Answer:

[tex]10 + \frac{8}{u}[/tex]

Step-by-step explanation:

Given

10 [tex]plus[/tex] the  [tex]quotient[/tex]of 8 and u

Required

Represent as a mathematical expression

Square out the operators

10 [[tex]plus[/tex]] the  [[tex]quotient[/tex]] of 8 and u

[tex]plus => +[/tex]

[tex]quotient => /[/tex]

Replace the operators with their signs

[tex]10 + \frac{8}{u}[/tex]

Help plz....................

Answers

Answer with  explanation:

y+1 = 26     ;      y = 26-1 = 25

x-2 = 19           ;    x = 19+ 2 = 21

I hope im roght!!

ill mark brainlist plss help

Answers

Answer:

it's the3rd one

Step-by-step explanation:

it's is 182 feet

I am confused on how to solve this. NOTE: the lower limit for the second function is (-6) NOT 6. Wouldn't let me type it in correctly.[tex]\int\limits^6_3 {|x-4|} \, dx + \int\limits^0_6 {\sqrt{36-x^2} } \, dx[/tex]

Answers

I think how you approach this depends on your knowledge of calculus.

If you don't know how to compute definite integrals yet, but you do know that they represent signed areas under curves, then you can plot both curves |x - 4| and √(36 - x ²), then recognize that the areas represented by these integrals are areas of geometric shapes. (See attached images)

First integral: if you plot |x - 4| on the interval [3, 6], you'll see that the integral corresponds to the area of two triangles. One of them has base = height = 1, and the other has base = height = 2. Then

[tex]\displaystyle\int_3^6|x-4|\,\mathrm dx=\frac12\times1\times1+\frac12\times2\times2=\frac52[/tex]

Second integral: if [tex]y=\sqrt{36-x^2}[/tex], then [tex]x^2+y^2=6^2[/tex], meaning this curve is the upper half of a circle with radius 6. On the interval [-6, 0], the area amounts to 1/4 of the total area of such a circle, so that

[tex]\displaystyle\int_{-6}^0\sqrt{36-x^2}\,\mathrm dx=\frac{\pi\times6^2}4=9\pi[/tex]

* * *

If you already know a few things about calculus and integration, you can compute these areas directly.

First integral:

[tex]\displaystyle\int_3^6|x-4|\,\mathrm dx=\int_3^4(4-x)\,\mathrm dx+\int_4^6(x-4)\,\mathrm dx[/tex]

[tex]\displaystyle\int_3^6|x-4|\,\mathrm dx=\left(4x-\frac{x^2}2\right)\bigg|_{x=3}^{x=4}+\left(\frac{x^2}2-4x\right)\bigg|_{x=4}^{x=6}[/tex]

[tex]\displaystyle\int_3^6|x-4|\,\mathrm dx=\left(\left(4\times4-\frac{4^2}2\right)-\left(4\times3-\frac{3^2}2\right)\right)+\left(\left(\frac{6^2}2-4\times6\right)-\left(\frac{4^2}2-4\times4\right)\right)[/tex]

[tex]\displaystyle\int_3^6|x-4|\,\mathrm dx=\frac52[/tex]

Second integral:

Substitute x = 6 sin(t ) and dx = 6 cos(t ) dt, then

[tex]\displaystyle\int_{-6}^0\sqrt{36-x^2}\,\mathrm dx=\int_{-\frac\pi2}^0\sqrt{6^2-(6\sin(t))^2} (6\cos(t))\,\mathrm dt[/tex]

[tex]\displaystyle\int_{-6}^0\sqrt{36-x^2}\,\mathrm dx=36\int_{-\frac\pi2}^0\cos (t) \sqrt{1-\sin^2(t)} \,\mathrm dt[/tex]

[tex]\displaystyle\int_{-6}^0\sqrt{36-x^2}\,\mathrm dx=36\int_{-\frac\pi2}^0\cos (t) \sqrt{\cos^2(t)} \,\mathrm dt[/tex]

[tex]\displaystyle\int_{-6}^0\sqrt{36-x^2}\,\mathrm dx=36\int_{-\frac\pi2}^0\cos (t) |\cos(t)| \,\mathrm dt[/tex]

For t ∈ [-π/2, 0], cos(t ) > 0, so |cos(t )| = cos(t ) :

[tex]\displaystyle\int_{-6}^0\sqrt{36-x^2}\,\mathrm dx=36\int_{-\frac\pi2}^0\cos^2(t)\,\mathrm dt[/tex]

Recall the half-angle identity,

cos²(t ) = (1 + cos(2t )) / 2

[tex]\displaystyle\int_{-6}^0\sqrt{36-x^2}\,\mathrm dx=18\int_{-\frac\pi2}^0(1+\cos(2t))\,\mathrm dt[/tex]

[tex]\displaystyle\int_{-6}^0\sqrt{36-x^2}\,\mathrm dx=18\left(t+\frac{\sin(2t)}2\right)\bigg|_{t=-\frac\pi2}^{t=0}[/tex]

[tex]\displaystyle\int_{-6}^0\sqrt{36-x^2}\,\mathrm dx=18\left(\left(0+\frac{\sin(2\times0)}2\right)-\left(-\frac\pi2+\frac{\sin\left(2\times\left(-\frac\pi2\right)\right)}2\right)\right)[/tex]

[tex]\displaystyle\int_{-6}^0\sqrt{36-x^2}\,\mathrm dx=9\pi[/tex]

4. Aaliyah swims at an average speed of 8 meters per second, how long will it
take her to complete the race of 200 meters' length? *

Answers

25 seconds. Hope this helps.

Please help me math inequality grade 8

Answers

Answer: x > 2/3

Step-by-step explanation:

-1 - x/2 < x

Simplify:

-1/2x + 1 < x

Subtract x from both sides:

-1/2x + 1 - x < x - x

-3/2x + 1 < 0

Subtract 1 from both sides:

-3/2x + 1 - 1 < 0 - 1

-3/2x < -1

Multiply both sides by 2/(-3):

2/(-3) (-3/2) < 2/(-3) (-1)

x > 2/3

The TV has a volume of 2,808 in³. The width measures 24 inches, and the height measures 18 inches. What is the depth of the TV? 18 in 6.5 in 24 in​

Answers

Answer:

quisiera ayudarte pero no hablo inglés

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