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1 year ago

Help OvO with this math question-

Mathematics

2 answers:

I am Lyosha [343]1 year ago

8 0

Answer:

Step-by-step explanation:

harkovskaia [24]1 year ago

6 0

Answer:

Step-by-step explanation:

40 x 80 = 3200

120 x 100 = 12000

3200 + 12000 = 15200

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The Highway Safety Department wants to study the driving habits of individuals. A sample of 40 cars traveling on a particular st

Ipatiy [6.2K]

Answer:

We need a sample size of at least 101

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.99}{2} = 0.005$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.005 = 0.995$ , so $z = 2.575$

Now, find the margin of error M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

What sample size is needed to estimate the true average speed to within 2 mph at 99% confidence?

We need a sample of at least n.

n is found when M = 2. So

$M = z*\frac{\sigma}{\sqrt{n}}$

$2 = 2.575*\frac{7.8}{\sqrt{n}}$

$2\sqrt{n} = 2.575*7.8$

$\sqrt{n} = \frac{2.575*7.8}{2}$

$(\sqrt{n})^{2} = (\frac{2.575*7.8}{2})^{2}$

$n = 100.85$

Rounding up

We need a sample size of at least 101

8 0

2 years ago

Read 2 more answers

What value of x is in the solution set of 9(2x + 1) < 9x - 18? <br> -4<br> -3<br> -2<br> -1

Anastaziya [24]

Answer:

The only possible answer that is correct is the first one, x = -4.

Step-by-step explanation:

Simplify the given inequality as much as possible, and then substitute each of the given x values one by one to determine which is in the solution set.

9(2x + 1) < 9x - 18 becomes 18x + 9 < 9x - 18, which, if reduced by dividing all four terms by 9, becomes 2x + 1 < x - 2.

Simplifying further, we get x < - 3. The only possible answer that is correct is the first one, x = -4. -4 < -3 is true.

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elena55 [62]

Answer:

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Step-by-step explanation:

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