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3 years ago

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Elena and Jada are 24 miles apart on a path when they start moving toward each other. Elena runs at a constant speed of 5 miles

per hour, and Jada walks at a constant speed of 3 miles per hour. How many hours does it take until Elena and Jada meet?

1 answer:

UNO [17]3 years ago

4 0

It will take 3 hours

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An automobile manufacturer who wishes to advertise that one of its models achieves 30 mpg (miles per gallon) decides to carry ou

Katyanochek1 [597]

Answer:

$t=\frac{29.35-30}{\frac{1.365}{\sqrt{6}}}=-1.17$

$p_v =P(t_{(5)}$

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.

We can say that at 5% of significance the true mean is not significantly less than 30 so then the claim that true average fuel efficiency is (at least) 30 mpg makes sense

Step-by-step explanation:

Data given and notation

The mean and sample deviation can be calculated from the following formulas:

$\bar X =\frac{\sum_{i=1}^n x_i}{n}$

$s=\sqrt{\frac{\sum_{i=1}^n (x_i -\bar X)}{n-1}}$

$\bar X=29.35$ represent the sample mean

$s=1.365$ represent the sample standard deviation

$n=6$ sample size

$\mu_o =30$ represent the value that we want to test

$\alpha=0.05$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the true mean is lower than 30 or no, the system of hypothesis are :

Null hypothesis: $\mu \geq 30$

Alternative hypothesis: $\mu < 30$

Since we don't know the population deviation, is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-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:

$t=\frac{29.35-30}{\frac{1.365}{\sqrt{6}}}=-1.17$

P-value

We need to calculate the degrees of freedom first given by:

$df=n-1=6-1=5$

Since is a one-side left tailed test the p value would given by:

$p_v =P(t_{(5)}$

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.

We can say that at 5% of significance the true mean is not significantly less than 30 so then the claim that true average fuel efficiency is (at least) 30 mpg makes sense

5 0

2 years ago

A container can hold no more than 80 lb. Rick fills the box with books that each weigh 2 lb and a statue that weighs 10 lb. Whic

Bad White [126]

2B + 10 ≤ 80.....................

6 0

3 years ago

Match each question to the correct problem.

Maslowich

<h2>Answer:</h2>

<em>(Check attached images).</em>

<h2>Step-by-step explanation:</h2>

<h3>Exercise 1.</h3>

a. Convert to decimals.

To order the numbers from least to greaters, convert them to decimals and compare.

$5.2(percent)=0.052\\ \\\frac{1}{7} =0.1429\\\\ -0.8=-0.8000\\ \\\frac{-11}{5} =-2.2$

b. Select the second least number.

-0.8.

<h3>Exercise 2.</h3>

a. Convert to decimals.

$-3.4(percent)=-0.034\\ \\-0.031\\\\ -0.2\\ \\-\sqrt{0.8}= -0.8944$

b. Select the correct number.

$-\frac{1}{5}$ .

<h3>Exercise 3.</h3>

a. Convert to decimals.

<em>After seeing that there are negative and positive numbers, and with the premise that negative numbers are </em><u><em>always</em></u><em> lesser than positive numbers, we'll only compare the positive numbers.</em>

<em>59%=0.59</em>

<em>3/5=0.6</em>

<em />

b. Select the correct number.

3/5.

<h3>Exercise 4.</h3>

a. Convert to decimals.

-0.35

-3.5%= -0.035

b. Conclude.

Seeing that -3.5% is less than -0.35, the symbol that makes the statement true is ">".

<h3>Exercise 5.</h3>

a. Try to visually estimate b.

B appears to have a value of -0.9.

b. Convert the numbers to decimals.

-3.4%= -0.034

-0.031

-1/5= -0.2

$-\sqrt{0.8}= -0.8944$

c. Select the correct answer.

<em>Since we estimated the value of b as -0.9, the number that best adequates to its value is </em> $-\sqrt{0.8}$ .

<h3>Exercise 6.</h3>

a. Convert to decimals.

<em>After seeing that there are negative and positive numbers, and with the premise that negative numbers are </em><u><em>always</em></u><em> lesser than positive numbers, we'll only compare the positive numbers.</em>

5.2%= 0.052

1/7= 0.1429

b. Select the correct number.

5.2% is the second largest.

<h3>Exercise 7.</h3>

a. Convert to decimals.

6/7= 0.857143

0.857

b. Select the correct answer.

Seeing that 0.857 is marked as an approximate by the

ellipsis, and considering that 6/7 is an irrational numbers, we can conclude that the number that better fits the situation and makes the statement true is "=".

<h3>Exercise 8.</h3>

a. Convert to decimals.

<em>After seeing that there are negative and positive numbers, and with the premise that negative numbers are </em><u><em>always</em></u><em> lesser than positive numbers, we'll only compare the negative numbers.</em>

<em>-4.6</em>

<em /> $-\sqrt{21} =-4.5826$

b. Select the correct answer.

The smallest number is -4.6.

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1 year ago

Helpppppppp pls help .

dsp73

Answer: X= 1 2 3 4 Y= 5 8 11 14

Step-by-step explanation: i tried my best

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2 years ago

Read 2 more answers

Evaluate 5x + (-2x 2) for x = 3.<br><br> a. 21<br> b. -3<br> c. 11

Vladimir79 [104]

Answer:

C. 11

Step-by-step explanation:

Assuming the problem is 5x + (-2 * 2) with x equals 3.

5(3)+(-2*2)

15+(-4)=

15-4=11

5 0

3 years ago

Read 2 more answers