I need help please can someone answer all of these? ill put a good amount of points

2.

NemiM [27]

Answer:

0.444444

Step-by-step explanation:

4*2 - 4x + 1 = 0

8 - 4x +1 = 0

9 = 4x

x = 4/9 = 0.444444

4 0

3 years ago

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A light bulb manufacturer guarantees that the mean life of a certain type of light bulb is at least 732 hours. A random sample o

soldi70 [24.7K]

Answer:

$z=\frac{704-732}{\frac{65}{\sqrt{28}}}=-2.279$

$p_v =P(z$

If we compare the p value and the significance level given for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we can reject the null hypothesis, and the the true mean is significantly lower than 732 hours so we have enough evidence to reject the claim

Step-by-step explanation:

Data given and notation

$\bar X=704$ represent the sample mean

$\sigma=65$ represent the standard deviation for the population

$n=28$ sample size

$\mu_o =732$ represent the value that we want to test

$\alpha$ 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 determine if the true mean is at least 732 or no, the system of hypothesis would be:

Null hypothesis: $\mu \geq 732$

Alternative hypothesis: $\mu < 732$

We know the population deviation, so for this case 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:

$z=\frac{704-732}{\frac{65}{\sqrt{28}}}=-2.279$

Calculate the P-value

Since is a one-side lower test the p value would be:

$p_v =P(z$

Conclusion

If we compare the p value and the significance level given for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we can reject the null hypothesis, and the the true mean is significantly lower than 732 hours so we have enough evidence to reject the claim

5 0

3 years ago

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What is an equation of the line that is parallel to y=9−4x and passes through (0, 7)?

Ray Of Light [21]

Parallel lines have the exact same slope. In y = mx + b form, the line we were given is y = -4x+9, where -4 is the slope and 9 is the y intercept. If the "new" line passes through (0, 7), we have the x and y and slope we need to write this new equation. In y=mx+b, y is the y coordinate of the given point: 7, x is the x coordinate in the given point: 0. The slope, remember, is -4. We fill in accordingly and solve for b. 7 = -4(0)+b and b = 7. Filling that back in we will have a new equation y = -4x=7, parallel to the given line.

8 0

3 years ago

Not sure how to do this

OLEGan [10]

It's pretty simple! So it looks like you are learning proportions. You would cross multiply to achieve your answer.

First, let's do your first problem:

2 12
--- = ----
5 n

You would take 5 and multiply it by 12 and get 60! Then you would do the same with 2 times n, giving you 2n (because you do not know what n represents YET.)

Now you should have this:
60=2n OR 2n=60

We must isolate our variable, in order to do that, get rid of two! But how? You would do this by dividing 2n by 2. Yet in equations, when you do something to one side, you must do it to the other because they must be EQUAL! (hence the "equa-" in equation)

2n=60
--- ---
2 2 DIVIDE 2 into 60
----------
n= 30 Simplify!

Your final answer for the first question is n= 30!

8 0

4 years ago

Find the ratio of:<br> (a) 5 km to 400 m<br> (b) 2 hours to 160 minutes

aleksandr82 [10.1K]

Answer:

Answer - a) 1:80

b) 1:80

Step-by-step explanation:

All the ratio should be written in lowest form. these are the answers for both the questions.

Pls Mark Brainliest !!!!!!!!!!!!!!

6 0

2 years ago

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