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3 years ago

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Danny says 7 and -7 are different numbers. Mae says 7 and -7 are both equal 0. Luis says 7 and -7 are the same number. akik says

7 and -7 combine to make 0. who is correct? Use mathematics to justify your choice of who is correct.

1 answer:

yaroslaw [1]3 years ago

5 0

Answer:

Akik is correct. -7+7=0.

Step-by-step explanation:

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Suppose μ1 and μ2 are true mean stopping distances at 50 mph for cars of a certain type equipped with two different types of bra

Stella [2.4K]

Answer:

The 95% confidence interval would be given by $-23.44 \leq \mu_1 -\mu_2 \leq -8.16$

Step-by-step explanation:

Previous concepts

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".

$\bar X_1 =114.1$ represent the sample mean 1

$\bar X_2 =129.9$ represent the sample mean 2

n1=5 represent the sample 1 size

n2=2 represent the sample 2 size

$s_1 =5.08$ sample standard deviation for sample 1

$s_2 =5.37$ sample standard deviation for sample 2

$\mu_1 -\mu_2$ parameter of interest.

Confidence interval

The confidence interval for the difference of means is given by the following formula:

$(\bar X_1 -\bar X_2) \pm t_{\alpha/2}\sqrt{\frac{s^2_1}{n_1}+\frac{s^2_2}{n_2}}$ (1)

The point of estimate for $\mu_1 -\mu_2$ is just given by:

$\bar X_1 -\bar X_2 =114.1-129.9=-15.8$

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n_1 +n_2 -1=5+5-2=8$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,8)".And we see that $t_{\alpha/2}=\pm 2.31$

The standard error is given by the following formula:

$SE=\sqrt{\frac{s^2_1}{n_1}+\frac{s^2_2}{n_2}}$

And replacing we have:

$SE=\sqrt{\frac{5.08^2}{5}+\frac{5.37^2}{5}}=3.306$

Confidence interval

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

$-15.8-2.31\sqrt{\frac{5.08^2}{5}+\frac{5.37^2}{5}}=-23.437$

$-15.8+2.31\sqrt{\frac{5.08^2}{5}+\frac{5.37^2}{5}}=-8.163$

So on this case the 95% confidence interval would be given by $-23.44 \leq \mu_1 -\mu_2 \leq -8.16$

8 0

3 years ago

Tell wether the given value is a solution of the inequality.

Lena [83]

N is a placeholder for a number. In this case, it is 4

We will replace every copy of 'n' with '4' and then simplify

So n+8 turns into 4+8 which simplifies to 12

Is 12 less than or equal to 13? Yes it is. Specifically it is less than 13. So n = 4 is part of the solution set.

Here is how you'd write it all out using algebra

$n+8 \le 13$

$4+8 \le 13$

$12 \le 13$

The last inequality is true so the first inequality is true when n = 4. This is another way to see that n = 4 is a solution.

3 0

3 years ago

You are training for a 5K race. This morning you ran 10 miles in 1 hour. If you run the race at this speed, how many minutes wil

NeX [460]

Answer:

4 hours

Step-by-step explanation:

3 0

3 years ago

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If there are 80 rides in total,how many are made for kids 48 inches and taller

Agata [3.3K]

This would 70% of 80. To find this multiply (7/10) by 80 to get your answer: 56.

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4 years ago

Can you pls Help fast as you can?

Scilla [17]

Answer: So what I would do first is add 14 and 58 together, then subtract it from 212 to get 140.

Then subtract 34 gallons from 140 gallons, to get 106. So I think it’s 106, Sorry if I’m wrong...

Step-by-step explanation:

8 0

2 years ago

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