Slove for x <br><br> 3x+9y=24

A demographer wants to measure life expectancy in countries 1 and 2. Let μ1 and μ2 denote the mean life expectancy in countries

Art [367]

Answer:

For this case we want to test if life expectancy in country 1 is more than 10 years lower than in country 2, (alternatibe hypothesis), so then the system of hypothesis are:

Null hypothesis: $\mu_1 \leq \mu_2 -10$

Alternative hypothesis: $\mu_1 > \mu_2 -10$

Or equivalently:

Null hypothesis: $\mu_1 - \mu_2 \leq 10$

Alternative hypothesis: $\mu_1 - \mu_2 >10$

Step-by-step explanation:

Previous concepts

A hypothesis is defined as "a speculation or theory based on insufficient evidence that lends itself to further testing and experimentation. With further testing, a hypothesis can usually be proven true or false".

The null hypothesis is defined as "a hypothesis that says there is no statistical significance between the two variables in the hypothesis. It is the hypothesis that the researcher is trying to disprove".

The alternative hypothesis is "just the inverse, or opposite, of the null hypothesis. It is the hypothesis that researcher is trying to prove".

Solution to the problem

For this case we want to test if life expectancy in country 1 is more than 10 years lower than in country 2, (alternatibe hypothesis), so then the system of hypothesis are:

Null hypothesis: $\mu_1 \leq \mu_2 -10$

Alternative hypothesis: $\mu_1 > \mu_2 -10$

Or equivalently:

Null hypothesis: $\mu_1 - \mu_2 \leq 10$

Alternative hypothesis: $\mu_1 - \mu_2 >10$

7 0

2 years ago

The table gives estimates of the world population, in millions, from 1750 to 2000. (Round your answers to the nearest million.)

BaLLatris [955]

Answer:

A.) 1508 ; 1870

B.) 2083

C.) 3972

Step-by-step explanation:

General form of an exponential model :

A = A0e^rt

A0 = initial population

A = final population

r = growth rate ; t = time

1)

Using the year 1750 and 1800

Time, t = 1800 - 1750 = 50 years

Initial population = 790

Final population = 980

Let's obtain the growth rate :

980 = 790e^50r

980/790 = e^50r

Take the In of both sides

In(980/790) = 50r

0.2155196 = 50r

r = 0.2155196/50

r = 0.0043103

Using this rate, let predict the population in 1900

t = 1900 - 1750 = 150 years

A = 790e^150*0.0043103

A = 790e^0.6465588

A = 1508.0788 ; 1508 million people

In 1950;

t = 1950 - 1750 = 200

A = 790e^200*0.0043103

A = 790e^0.86206

A = 1870.7467 ; 1870 million people

2.)

Exponential model. For 1800 and 1850

Initial, 1800 = 980

Final, 1850 = 1260

t = 1850 - 1800 = 50

Using the exponential format ; we can obtain the rate :

1260 = 980e^50r

1260/980 = e^50r

Take the In of both sides

In(1260/980) = 50r

0.2513144 = 50r

r = 0.2513144/50

r = 0.0050262

Using the model ; The predicted population in 1950;

In 1950;

t = 1950 - 1800 = 150

A = 980e^150*0.0050262

A = 980e^0.7539432

A = 2082.8571 ; 2083 million people

3.)

1900 1650

1950 2560

t = 1900 - 1950 = 50

Using the exponential format ; we can obtain the rate :

2560 = 1650e^50r

2560/1650 = e^50r

Take the In of both sides

In(2560/1650) = 50r

0.4392319 = 50r

r = 0.4392319/50

r = 0.0087846

Using the model ; The predicted population in 2000;

In 2000;

t = 2000 - 1900 = 100

A = 1650e^100*0.0087846

A = 1650e^0.8784639

A = 3971.8787 ; 3972 million people

3 0

2 years ago

Solving one to two step equations . algebra 1 .

frozen [14]

Answer:

1.) k = 5

2.) n = -20

3.) p = -13

4.) m = -450

5.) b = -38

6.) n = -24

7.) x = 21

8.) x = 12

9.) b = -2

10.) b = 5

Step-by-step explanation:

To solve all equations, do the reciprocal, or opposite of what is being done. For example, if a number and a variable are being multiplied, you would divide by the number to solve.

1.) 55 = 11k

(11 and k are being multiplied, so you would divide)

Divide by 11 on both sides:

55 = 11k

/11 /11

5 = k

2.) Add 15 on both sides:

n - 15 = -35

+15 +15

n = -20

3.) Divide by -6 on both sides:

78 = -6p

/-6 /-6

-13 = p

4.) Multiply by 18 on both sides:

m/18 = -25

18(m/18) = (-25)18

m = -450

5.) Add 20 on both sides:

18 = -20 - b

+20 +20

38 = -b

Divide by -1 on both sides:

38 = -b

/-1 /-1

-38 = b

6.) Subtract 12 on both sides:

12 + n/4 = 6

-12 -12

n/4 = -6

Multiply by 4 on both sides:

4(n/4) = (-6)4

n = -24

7.) Multiply by 2 on both sides:

2(-7 + x/2) = (7)2

-7 + x = 14

Add 7 on both sides:

-7 + x = 14

+7 +7

x = 21

8.) Subtract 2 on both sides:

-4x + 2 = -22

-2 -2

-4x = -24

Divide by -4 on both sides:

-4x = -24

/-4 /-4

x = 12

9.) Add 9 on both sides:

7 = -8b - 9

+9 +9

16 = -8b

Divide by -8 on both sides:

16 = -8b

/-8 /-8

-2 = b

10.) Multiply by -3 on both sides:

-3(b - 14/-3) = (3)-3

b - 14 = -9

Add 14 on both sides:

b - 14 = -9

+14 +14

b = 5

3 0

3 years ago

Please help FAST:

Alex_Xolod [135]

Answer:

car a, car b

Step-by-step explanation:

car a 2x + 2= 4x

car b 3x + 3= 9x

both cars 13x

8 0

2 years ago

Which of the following is not a property of a chi-square distribution?

laiz [17]

Answer:

c) Is not a property (hence (d) is not either)

Step-by-step explanation:

Remember that the chi square distribution with k degrees of freedom has this formula

$\chi_k^2 = \matchal{N}_1^2 + \matchal{N}_2^2 + ... + \, \matchal{N}_{k-1}^2 + \matchal{N}_k^2$

Where N₁ , N₂m .... $N_k$ are independent random variables with standard normal distribution. Since it is a sum of squares, then the chi square distribution cant take negative values, thus (c) is not true as property. Therefore, (d) cant be true either.

Since the chi square is a sum of squares of a symmetrical random variable, it is skewed to the right (values with big absolute value, either positive or negative, will represent a big weight for the graph that is not compensated with values near 0). This shows that (a) is true

The more degrees of freedom the chi square has, the less skewed to the right it is, up to the point of being almost symmetrical for high values of k. In fact, the Central Limit Theorem states that a chi sqare with n degrees of freedom, with n big, will have a distribution approximate to a Normal distribution, therefore, it is not very skewed for high values of n. As a conclusion, the shape of the distribution changes when the degrees of freedom increase, because the distribution is more symmetrical the higher the degrees of freedom are. Thus, (b) is true.

6 0

3 years ago

Slove for x 3x+9y=24