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3 years ago

Need help plz i am so bad at math

Mathematics

1 answer:

VLD [36.1K]3 years ago

5 0

Answer:

for 72---72/2=36

for 10---100/2(10)=5

Step-by-step explanation:

72/2=36

100/2(10)

2*10=20

100/20=5

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How can 38/6 be expressed as a decimal?

seraphim [82]

38/6 = 19/3
divide 19 by 3 :-

= 6.333....

The 3 is recurring

8 0

3 years ago

A government report gives a 99% confidence interval for the proportion of welfare recipients who have been receiving welfare ben

juin [17]

Answer:

The estimation for the proportion for this case is $\hat p = 0.21$

And we know that the 99% confidence interval is given by:

$0.21 \pm 0.045$

So then the margin of error at 99% of confidence is 0.045, and the margin of error is given by this formula:

$ME= z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

If we decrease the confidence level this margin of error can't be higher than 0.045 so then the correct answer for this case would be:

d. 21% ± 4.8%

Because if the z value decrease from 2.58 to 1.96 not makes sense that the margin of error increase from 0.045(4.5%) to 0.048(4.8%)

Step-by-step explanation:

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".

Solution to the problem

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

The confidence interval would be given by this formula

$\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

For the 95% confidence interval the value of $\alpha=1-0.95=0.05$ and $\alpha/2=0.025$ , with that value we can find the quantile required for the interval in the normal standard distribution.

$z_{\alpha/2}=1.96$

For the 99% confidence interval the value of $\alpha=1-0.99=0.01$ and $\alpha/2=0.005$ , with that value we can find the quantile required for the interval in the normal standard distribution.

$z_{\alpha/2}=2.58$

The estimation for the proportion for this case is $\hat p = 0.21$

And we know that the 99% confidence interval is given by:

$0.21 \pm 0.045$

So then the margin of error at 99% of confidence is 0.045, and the margin of error is given by this formula:

$ME= z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

If we decrease the confidence level this margin of error can't be higher than 0.045 so then the correct answer for this case would be:

d. 21% ± 4.8%

Because if the z value decrease from 2.58 to 1.96 not makes sense that the margin of error increase from 0.045(4.5%) to 0.048(4.8%)

5 0

3 years ago

6 is 25% of what number?

Vsevolod [243]

24 cause 25% is basically 1/4 so its 4 times 6 so its 24

4 0

3 years ago

A refrigerator cools a bottle of water 2 degrees per minute. how many minutes will it take to lower its temperature from 90 degr

HACTEHA [7]

<span>It will take 20 minutes. The fridge needs to cool down by 90-50=40degrees. The fridge cools at 2 degrees per minute, i.e. 40/2=20 minutes total.</span>

8 0

3 years ago

a geometric series where the first term is -12, the last term is -972, and each term after the first is triple the previous term

Luba_88 [7]

Answer:

the geometric series is a(n) = -12(3)^(n-1)

Step-by-step explanation:

"Triple" denotes multiplication by 3. Thus, the common factor here is 3.

The general formula for a geometric series is a(n) = a(1)(r)^(n-1), where a(1) is the first term, r is the common ratio.

Here, we have a(n)= (-12)(3)^(n-1) = -972.

We need to solve this for n, which represents the last term.

The first step towards solving for n is to divide both sides by -12:

3^(n-1) = 81

To solve for n-1, rewrite 81 as 3^4. Then we have:

3^(n-1) = 3^4, implying that (n-1) = 4 and that n = 5.

Then we know that it is the 5th term that equals -972.

In summary, the geometric series is a(n) = -12(3)^(n-1).

8 0

3 years ago