What is the value of z for the equation

An expression is shown.

Vikki [24]

Answer:

Step-by-step explanation:

2+8+3_5x1

7 0

3 years ago

Solve 4(3x+3)=15x+7-3x+5

Flura [38]

Answer:

Infinite amount of solutions

Step-by-step explanation:

Step 1: Write equation

4(3x + 3) = 15x + 7 - 3x + 5

Step 2: Solve for x

Distribute 4: 12x + 12 = 15x + 7 - 3x + 5
Combine like terms: 12x + 12 = 12x + 12
Subtract 12 on both sides: 12x = 12x
Divide both sides by 12: x = x

Here, we can see that x would be infinite amount of solutions. We can plug in any number x and it would render the equation true.

4 0

3 years ago

A city has a population of 230,000 people. Suppose that each year the population grows by 9%. What will the population be after

zloy xaker [14]

Answer:

Step-by-step explanation:

If it grows by 9% each year, you can simply do the current population times 109%. Because its an additional 9%.

230,000*109% = 250,700

After the first year, there is a population of 250,700 people.

250,700*109% = 273,263

After the second year, there is a population of 273,263 people.

273,263*109% = 297,856.67

After the third year, there is a population of 297,856.67 people.

297,856.67*109% = 324,663.77

After the fourth year, there is a population of 324,663.77 people.

324,663.77*109% = 353,883.509

After the fifth year, there is a population of 353,883.509 people.

353,883.509*109% = 385,733.025

After the sixth year, there is a population of 385,733.025 people

Round it up to 385,733 people.

7 0

3 years ago

Segment AE is a median for Triangle ABC.

Shalnov [3]

Step-by-step explanation:

$BC = BE + CE...(\because B-E-C) \\ \\ \therefore \: BC = 3x - 5 + x + 1 \\ \\ \therefore \: BC = 4x - 4 \\ \\ \huge \red{ \boxed{ \therefore \: BC = 4(x - 1)}}$

4 0

4 years ago

The following data lists the ages of a random selection of actresses when they won an award in the category of Best Actress, al

Valentin [98]

Answer:

a) $p_v =P(t_{(9)}$

The p value is higher than the significance level given 0.01, so then we can conclude that we FAIL to reject the null hypothesis. And we can say that the true difference for Best Actresses is not significantly lower than the mean for Best Actors at 1% of significance.

b) The 99% confidence interval would be given by (-21.469;2.069)

c) We got the same conclusion as part a, sicne the confidence interval contains the value 0, we FAIL to reject the null hypothesis that the difference between the two

Step-by-step explanation:

Part a

Let put some notation

x=actor's age , y = actress's age

x: 58 41 36 36 34 33 48 37 37 43

y: 26 27 34 26 35 29 23 42 30 34

The system of hypothesis for this case are:

Null hypothesis: $\mu_y- \mu_x \geq 0$

Alternative hypothesis: $\mu_y -\mu_x$

The first step is calculate the difference $d_i=y_i-x_i$ and we obtain this:

d: -32, -14, -2, -10, 1, -4, -25, 5, -7, -9

The second step is calculate the mean difference

$\bar d= \frac{\sum_{i=1}^n d_i}{n}= -9.7$

The third step would be calculate the standard deviation for the differences, and we got:

$s_d =\frac{\sum_{i=1}^n (d_i -\bar d)^2}{n-1} =11.451$

The 4 step is calculate the statistic given by :

$t=\frac{\bar d -0}{\frac{s_d}{\sqrt{n}}}=\frac{-9.7 -0}{\frac{11.451}{\sqrt{10}}}=-2.679$

The next step is calculate the degrees of freedom given by:

$df=n-1=10-1=9$

Now we can calculate the p value, since we have a left tailed test the p value is given by:

$p_v =P(t_{(9)}$

The p value is higher than the significance level given 0.01, so then we can conclude that we FAIL to reject the null hypothesis. And we can say that the true difference for Best Actresses is not significantly lower than the mean for Best Actors at 1% of significance.

Part b

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The confidence interval for the mean is given by the following formula:

$\bar d \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,9)".And we see that $t_{\alpha/2}=3.25$

Now we have everything in order to replace into formula (1):

$-9.7-3.25\frac{11.451}{\sqrt{10}}=-21.469$

$-9.7+3.25\frac{11.451}{\sqrt{10}}=2.069$

So on this case the 99% confidence interval would be given by (-21.469;2.069)

Part c

We got the same conclusion as part a, sicne the confidence interval contains the value 0, we FAIL to reject the null hypothesis that the difference between the two means is 0.

8 0

3 years ago