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DedPeter [7]

3 years ago

lass="latex-formula">

Mathematics

1 answer:

sasho [114]3 years ago

6 0

Answer:

x^2+5x-14

Step-by-step explanation:

Using FOIL method, we get (x^2)+(-2x)+(7x)+(-14), which is just x^2+5x-14

FOIL = First, Outer, Inner, Last

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How do you find the greatest common denominator, when comparing two numbers? Explain your thought process, in the example I prov

maksim [4K]

Answer:

20 is the greatest common denominator. You can find this by listing the factors of each number. The highest number that can fit into both individual numbers is the common denominator. Since 40 is just 20 doubled, and 20 is just 20 once, it fits into both numbers and is also the highest number that can fit.

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3 years ago

after selling a dozen copies of the daily newspaper, a newsstand had fewer than 79 copies left. how many copies did the newsstan

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3 years ago

The coffee shop owner explains that she will work 12 hours more than you do if you get the job. She will work 50 hours edch week

MrMuchimi

Answer:

The owner says that she will work 12 hours more than you if you get the job.

We know that she works 50 hours each week.

then, knowing that she works 50 hours per week and that she works 12 hours more than you, you have that, if H is the number of hours that you work per week, you have:

H + 12 = 50

Here says that the number of hours that you work, plus 12 hours, is equal to the number of hours that the owner works.

H = 50 - 12 = 38

This means that you would work 38 hours per week.

3 0

3 years ago

The following data were collected from 12 rain gauges in a park. Build a 95% CI for the mean rainfall at the park.

dybincka [34]

Answer:

Critical values: $t_{\alpha/2}=-2.201$ $t_{1-\alpha/2}=2.201$

95% confidence interval would be given by (3.646;4.472)

Step-by-step explanation:

1) 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".

The data is:

4.65 3.89 2.73 4.35 3.80 4.86 4.33 4.37 4.76 4.05 3.05 3.87

2) Compute the sample mean and sample standard deviation.

In order to calculate the mean and the sample deviation we need to have on mind the following formulas:

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

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

=AVERAGE(4.65,3.89,2.73, 4.35, 3.8, 4.86, 4.33, 4.37, 4.76, 4.05, 3.05, 3.87)

On this case the average is $\bar X= 4.059$

=STDEV.S(4.65,3.89,2.73, 4.35, 3.8, 4.86, 4.33, 4.37, 4.76, 4.05, 3.05, 3.87)

The sample standard deviation obtained was s=0.6503

3) Find the critical value t* Use the formula for a CI to find upper and lower endpoints

In order to find the critical value we need to take in count that our sample size n =12 <30 and on this case we don't know about the population standard deviation, so on this case we need to use the t distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . The degrees of freedom are given by: