Use rounding to estimate the product of 5, 555 and 4, 444. Round both numbers to the nearest thousand to find your answer.

An auto company claims that the fuel efficiency of its sedan has been substantially improved. A consumer advocate organization w

zzz [600]

Answer:

$t=\frac{\bar d -0}{\frac{s_d}{\sqrt{n}}}=\frac{0.983 -0}{\frac{1.685}{\sqrt{12}}}=2.021$

$df=n-1=12-1=11$

$p_v =P(t_{(11)}>2.021) =0.0342$

If we compare the the p value with the significance level provided $\alpha=0.1$ , we see that $p_v < \alpha$ , so then we can reject the null hypothesis. and there is a significant increase in the miles per gallon from 2017 to 2019 at 10% of significance.

Step-by-step explanation:

Previous concepts

A paired t-test is used to compare two population means where you have two samples in which observations in one sample can be paired with observations in the other sample. For example if we have Before-and-after observations (This problem) we can use it.

Let put some notation :

x=test value 2017 , y = test value 2019

x: 28.7 32.1 29.6 30.5 31.9 30.9 32.3 33.1 29.6 30.8 31.1 31.6

y: 31.1 32.4 31.3 33.5 31.7 32.0 31.8 29.9 31.0 32.8 32.7 33.8

Solution to the problem

The system of hypothesis for this case are:

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

Alternative hypothesis: $\mu_y -\mu_x >0$

Because if we have an improvement we expect that the values for 2019 would be higher compared with the values for 2017

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

d: 2.4, 0.3, 1.7,3,-0.2, 1.1, -0.5, -3.2, 1.4, 2, 1.6, 2.2

The second step is calculate the mean difference

$\bar d= \frac{\sum_{i=1}^n d_i}{n}= \frac{11.8}{12}=0.983$

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

$s_d =\frac{\sum_{i=1}^n (d_i -\bar d)^2}{n-1} =1.685$

We assume that the true difference follows a normal distribution. The 4th step is calculate the statistic given by :

$t=\frac{\bar d -0}{\frac{s_d}{\sqrt{n}}}=\frac{0.983 -0}{\frac{1.685}{\sqrt{12}}}=2.021$

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

$df=n-1=12-1=11$

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

$p_v =P(t_{(11)}>2.021) =0.0342$

If we compare the the p value with the significance level provided $\alpha=0.1$ , we see that $p_v < \alpha$ , so then we can reject the null hypothesis. and there is a significant increase in the miles per gallon from 2017 to 2019 at 10% of significance.

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What is the slope of the point (1÷4,3÷2)and (-1,-3)

Viefleur [7K]

Step-by-step explanation:<u>The slope calculator helps find the slope of any line through two given ... the slope of the line passing through the points (3,8) and (-2, 10) . ... A 1/20 slope is one that rises by 1 unit for every 20 units traversed horizontally.</u>

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Pythagorean Theorem Word Problems Mazel

mixer [17]

Is there supposed to be a picture here?? There isn’t.

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A bag of tiles contains 6 green 4 yellow and 5 blue tiles. If one tile is pulled at random what is the probability of NOT choosi

astra-53 [7]

3/5 or 60% probability of not choosing green

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solve the following system of equations. Enter the x-coordinate of the solution. Round answer to the nearest tenth. 5x+2y=22 -2x

melisa1 [442]

Answer:

A) 5x + 2y = 22

B) -2x + 6y = 3 We'll multiply A) by -3

A) -15x -6y = -66 Then we'll add B)

B) -2x + 6y = 3

-17x = -63

x = 3.7058823529

y = 1.7352941178

Step-by-step explanation:

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