PLEASE HELP!!! 39 POINTS!!!!

Examine the system of equations.

andre [41]

Answer:

x = -3

(-3,7)

Step-by-step explanation:

y = –3x – 2,

y = 7

We know the value of y, y=7

Substitute into the first equation

7 = –3x – 2

Add 2 to each side

7+2 = –3x – 2+2

9 = -3x

Divide each side by -3

9/-3 = -3x/-3

-3 = x

3 0

4 years ago

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A researcher would like to determine whether a new tax on cigarettes has had any effect on people’s behavior. During the year be

sammy [17]

Answer:

a) $p_v =2*P(z$

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, so we can conclude that the population mean is NOT significant different from 410 at 5% of significance.

b) $p_v =2*P(z$

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the population mean is significant different from 410 at 5% of significance.

c) The expplanation why we have different outcomes is because for part a we use a higher standard error compared to part b. So we have enough evidence on part b to reject the null hypothesis that we no have significant difference from 410.

Step-by-step explanation:

1) Part a

Previous concepts and data given

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".

$\bar X=386$ represent the sample mean

$\sigma=60$ represent the population standard deviation

n=9 represent the sample selected

$\alpha=0.05$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if we have significant difference on the mean, the system of hypothesis would be:

Null hypothesis: $\mu = 410$

Alternative hypothesis: $\mu \neq 410$

If we analyze the size for the sample is < 30 but we know the population deviation so is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{386-410}{\frac{60}{\sqrt{9}}}=-1.2$

P-value

Since is a two side test the p value would be:

$p_v =2*P(z$

Conclusion

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, so we can conclude that the population mean is NOT significant different from 410 at 5% of significance.

2) Part b

State the null and alternative hypotheses.

The system of hypothesis not changes:

Null hypothesis: $\mu = 410$

Alternative hypothesis: $\mu \neq 410$

Same statistic:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

Calculate the statistic

But now the population deviation changes $\sigma=30$ . We can replace in formula (1) the info given like this:

$z=\frac{386-410}{\frac{30}{\sqrt{9}}}=-2.4$

P-value

Since is a two side test the p value would be:

$p_v =2*P(z$

Conclusion

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the population mean is significant different from 410 at 5% of significance.

7 0

3 years ago

Chad likes to play Bingo at the nearby American Legion Hall. One day he goes into the hall with $14 in his pocket. When he comes

Natalija [7]

Answer:

1. $17

2.$2

Step-by-step explanation:

6 0

3 years ago

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Jivesh brought his Model B rocket on a camping trip near the top of a mountain. He wants to model how it descends down the mount

dybincka [34]

Answer:

i. 1.63 s

ii. The negative time cannot be used in this context

Step-by-step explanation:

i. Since h = −640t² and the rocket descends 1,690 m, h = -1,690 m (since there is a drop in height).

So, h = -640t²

t² = h/-640

t = √(- h/640)

Substituting h into the equation, we have

t = √(- h/640)

t = √[-(-1,690)/640]

t = √2.640625

t = 1.625

t ≈ 1.63 s

ii. So, the negative time cannot be used in this context because, the height drop is negative.

8 0

3 years ago

5. Find a counterexample to show that the following con-

Bess [88]

Answer: see below

<u>Step-by-step explanation:</u>

Any value x such that |x| < 1 will make the conjecture false

<em>In simpler words, let x be a fraction between 0 and 1.</em>

One example: Let x = $\dfrac{1}{2}$

Then x⁴ = $\bigg(\dfrac{1}{2}\bigg)^4$

= $\dfrac{1}{16}$

$\dfrac{1}{16}$ < $\dfrac{1}{2}$

so the conjecture is false.

7 0

3 years ago