Can someone answer this please so I can go to the back page

Mathematics

1 answer:

igomit [66]3 years ago

7 0

Blake has 25 CD's.

25 times 3 = 75
75 + 7 = 82

Joel has 82 CD's.

If Joel has twice as many as Mariella, then divide 82 by 2 and you get 41.

Mariella has 41 CD's.

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The gradient of the line y= -2x -3

N76 [4]

Answer:

-2

Step-by-step explanation:

The equation of the line is written in y=mx+c form, where m is the gradient and c is the y-intercept.

In this case, your m is a -2 and your c is a -3.

Hence the gradient of the line is -2.

5 0

3 years ago

Brewed decaffeinated coffee contains some caffeine. We want to estimate the amount of caffeine in 8 ounce cups of decaf coffee a

rusak2 [61]

Answer:

We would have to take a sample of 62 to achieve this result.

Step-by-step explanation:

Confidence level of 95%.

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

$\alpha = \frac{1 - 0.95}{2} = 0.025$

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

That is z with a pvalue of $1 - 0.025 = 0.975$ , so Z = 1.96.

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.

Assume that the standard deviation in the amount of caffeine in 8 ounces of decaf coffee is known to be 2 mg.

This means that $\sigma = 2$

If we wanted to estimate the true mean amount of caffeine in 8 ounce cups of decaf coffee to within /- 0.5 mg, how large a sample would we have to take to achieve this result?

We would need a sample of n.

n is found when $M = 0.5$ . So