Jillian has been updating the design of a media streaming website. She wonders if users will spend more time on the site with the new design, so she designs a study. She starts with a random sample of 1,000 users and randomly assigns half of them to the old design and half of them to the new design. After a week, she notices that users with the new design spend significantly longer on the site than the users with the old design. Can we conclude that the new design caused users to spend more time on the site? Why? Choose 1 answer: A)Yes because the sample size was large, B) Yes, because the users were randomly assigned to treatment and control groups, C) Yes, because the users were randomly selected, D) Not necessarily, because the sample size was too small, E) Not necessarily, because this wasn’t an experiment.

Answer:

0.4435

Step-by-step explanation:

Given that :

X is normally distributed:

mean(m) = 1,000

standard deviation (s) = 250

probability that X lies between 800 and 1,100?

Using the relation :

X = 800

Zscore = (x - m) / s

Zscore = (800 - 1000) / 250

Zscore = - 200 / 250

Zscore = - 0.8

P(Z ≤ - 0.8) = 0.2119

X = 1100

Zscore = (x - m) / s

Zscore = (1100 - 1000) / 250

Zscore = 100 / 250

Zscore = 0.4

P(Z ≤ 0.4) = 0.6554

P(Z ≤ 0.4) - P(Z ≤ - 0.8)

0.6554 - 0.2119

= 0.4435

Answer:

C

Step-by-step explanation:

so

y=9 -> y=18

       *2

x=8 -> x=16

       *2

so x = 16

Answer:

the only logical way solving this question is:

if y=9 then x=8

if y=18 then x should be 16

Step-by-step explanation:

I cant find any other way to solve

Answer:

she uses 72 gallons

Step-by-step explanation:

just do 144/2 and the answer is 72

if you wanna check your answer just do 72x2 and it equals 144

Answer:

184.2 in^3

Step-by-step explanation:

vol of cone=

[tex]\pi {r}^{2} \frac{h}{3} [/tex]

[tex]3.14 \times 16 \times \frac{11}{3} [/tex]

=184.2

The answer is b. 15ft

Answer with step-by-step explanation:

First of all, ORDER OF OPERATIONS!! 2x/x is 2/1, which is 2. Then, subtract 1, which is 1.

2x ÷ x - 1 = 1

Same thing: x/x = 1. Subtract 1 from 1, which is 0.

x ÷ x - 1 = 0

1 + 0 = 1

Hope this helped!

Answer:

A.

Step-by-step explanation:

Answer:

=b^2+(9+2)b+18

=b^2+9b+2b+18

=b(b+9)+2(b+9)

=(b+9)(b+2)

Answer:

b = 5

mark me as brainliest plz!! :DD

Answer:

9>x>3

Step-by-step explanation:

the open side always faces the greater value

Answer:

57 days

Step-by-step explanation:

Given that:

t(0) = 26000

Growth rate (S'(t)) = 80t^1/2

Targeted number of subscribers = 49000

Take the integral of the growth rate :

∫80t^1/2dt = [(80t^(1/2 + 1)) / 1/2 + 1] + C

[(80t^(1/2 + 1)) / 1/2 + 1] + C = (80t^3/2) / 3/2 + C

(80t^3/2) * 3/2 + C = (160/3)t^3/2 + C

(160/3)t^3/2 + C

Let C = t(0)

(160/3)t^3/2 + 26000 = 49000

(160/3)t^3/2 = 49000 - 26000

(160/3)t^3/2 = 23000

Multiply both sides by 3/160

t^3/2 = 23000* 3/160

t^3/2 = 69000/160

t^3/2 = 431.25

t^(3/2 * 2/3) = 431.25^2/3

t = 57.080277

t = 57 days (approx.)

Answer: pretty sure the friend would get 2 donuts

Step-by-step explanation:

you should just have to times the yards by three like the second one is 12

Answer:

7(y+2)=6

Step-by-step explanation:

its right

Answer:

Y=2x-1

Step-by-step explanation:

In order to find the slope, its rise over run. So you would move from (0,-1) to the next point it intercepts, (1,1) and find it from there

As for the Y-Intercept, it would just be wherever the line connects with the Y axis, which happens to be (0,-1) or Negative 1.

Answer:

t>35

Step-by-step explanation:

Since Michael exercises more than 35 days, t is greater than 35. To express that in an inequality, the answer is t>35. Hope this helped!

Answer:

A

Step-by-step explanation:

Answer:

A) I hope I helped you ◉‿◉

Answer:

The wood was cut approximately 8679 years ago.

Step-by-step explanation:

At first we assume that examination occured in 2020. The decay of radioactive isotopes are represented by the following ordinary differential equation:

[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex] (Eq. 1)

Where:

[tex]\frac{dm}{dt}[/tex] - First derivative of mass in time, measured in miligrams per year.

[tex]\tau[/tex] - Time constant, measured in years.

[tex]m[/tex] - Mass of the radioactive isotope, measured in miligrams.

Now we obtain the solution of this differential equation:

[tex]\int {\frac{dm}{m} } = -\frac{1}{\tau}\int dt[/tex]

[tex]\ln m = -\frac{1}{\tau} + C[/tex]

[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)

Where:

[tex]m_{o}[/tex] - Initial mass of isotope, measured in miligrams.

[tex]t[/tex] - Time, measured in years.

And time is cleared within the equation:

[tex]t = -\tau \cdot \ln \left[\frac{m(t)}{m_{o}} \right][/tex]

Then, time constant can be found as a function of half-life:

[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (Eq. 3)

If we know that [tex]t_{1/2} = 5730\,yr[/tex] and [tex]\frac{m(t)}{m_{o}} = 0.35[/tex], then:

[tex]\tau = \frac{5730\,yr}{\ln 2}[/tex]

[tex]\tau \approx 8266.643\,yr[/tex]

[tex]t = -(8266.643\,yr)\cdot \ln 0.35[/tex]

[tex]t \approx 8678.505\,yr[/tex]

The wood was cut approximately 8679 years ago.

Answer:

6.25 hours

Step-by-step explanation:

this is rather simple really,

first, you have to work 40 hours a week

you have already worked 15 so now you can subtract that

40-15= 25hrs

if you have 4 more days of the week you divide the remaining hours by the days left

25/4= 6.25hrs

that would be the bare minimum of hours for you to work a 40 hour week.

Step-by-step explanation:

The order of the numbers doesn't matter, so we'll use combinations instead of permutations.  The number of combinations is:

₄₅C₈ = 215,553,195

So the probability of a ticket having the winning combination is 1 / 215,553,195.

The expected value to the state is:

E(X) = 10,000 (1) ($2) + 10,000 (1 / 215,553,195) (-$1,000,000)

E(X) = $19954

The expected value to you is:

E(X) = 10,000 (1) (-$2) + 10,000 (1 / 215,553,195) ($1,000,000)

E(X) = -$19954

Answer:

a. -14

b. -13

c. -5

d. -3

e. -12

f. 0

Step-by-step explanation:

hope it helps

Answer:

A is -14.

B is -13

C is -5

D is -3

E is -12

F is 0

Step-by-step explanation:

A, B, E both numbers are negative so you just add them together and add a negative sign.

C would read 4-9

D 10-7 and add a - to the answer

F is 6-6

Answer:

18

Step-by-step explanation:

The tens digit a is cubed (a³ ) still less than the biggest possible 1 -digit number . It can be only 0 or 1 , so even 2³ =8 ( in such case the unit digit is 15,- that's  not possible) .

0 can not be the the first digit in 2 digit number. So the only possible tens digit is 1. So the unit number is 1+7=8.

Answer 18

Answer:

18

Step-by-step explanation:

Answer:

Exact Form:

17/2

Decimal Form:

8.5

Mixed Number Form:

8 1/2

Answer:

C. -2n² - n + 5

Step-by-step explanation:

In expression C, the coefficient of the n term is -1;

  The expression in choice C is given as:

               -2n² - n + 5

The coefficient is the number before a variable;

  For n², the coefficient is -2

    for n, the coefficient is -1

Answer:

nope

Step-by-step explanation:

Answer:

22.82

Step-by-step explanation:

can u plz mark me as brainliest??

Answer:

22.82

Step-by-step explanation:

3.1*1.4 = 4.34

27.16-4.34 = 22.82

[edited, I messed up the order of operations before, sorry]