Help please! I don't understand

Help me please! Math homework. I’m in 7th grade, and I lost all my brain cells

maria [59]

Answer:

A) 32, 40, 48, 56, 64, 72, 80

B) y-axis goes 4, 8, 12

x-axis goes 4, 8, 12, 16, 20

3 0

3 years ago

After 3.5 hours ,pasha had traveled 217 miles if she travels at the constant speed how far will she have travelled after 4 hours

vesna_86 [32]

Answer:

248 miles

Step-by-step explanation:

we know that

After 3.5 hours ,Pasha had traveled 217 miles

so

using proportion

Find out how many miles she will have traveled after 4 hours

$\frac{3.5}{217}\ \frac{hours}{miles}=\frac{4}{x}\ \frac{hours}{miles}\\\\x=217(4)/3.5\\\\x=248\ miles$

4 0

3 years ago

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.

4 0

3 years ago

Solve the missing side in the right triangle below

maw [93]

Answer: the root of 145 so b

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

How do you solve 21÷1/3

nordsb [41]

Answer:

63

Step-by-step explanation:

<u>When dividing by a fraction, it is the same a multiplying that fraction but the reciprocal of it.</u>

21 / 1/3 is same as 21 * 3/1

63

Answer: 63

8 0

3 years ago