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Mathematics

1 answer:

Vadim26 [7]3 years ago

3 0

I think I’d B help this helps

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An article regarding interracial dating and marriage recently appeared in the Washington Post. Of the 1,709 randomly selected ad

VMariaS [17]

Answer:

The 95% confidence interval for the percent of all black adults who would welcome a white person into their families is (0.8222, 0.8978).

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

For this problem, we have that:

323 blacks, 86% of blacks said that they would welcome a white person into their families. This means that $n = 323, p = 0.86$

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.86 - 1.96\sqrt{\frac{0.86*0.14}{323}} = 0.8222$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.86 + 1.96\sqrt{\frac{0.86*0.14}{323}} = 0.8978$

The 95% confidence interval for the percent of all black adults who would welcome a white person into their families is (0.8222, 0.8978).

5 0

3 years ago

Principal=$100 rate=5% years=3 what is the interest?

hammer [34]

Answer:

Interest would be $15 every 3 years

Step-by-step explanation:

Interest = Principal x Rate x Time

Interest = 100 x 5% x 3

Interest = 5 x 3

Interest = 15

6 0

3 years ago

The sum of the first n terms of an arithmetic sequence is n/2(4n + 20).

lesantik [10]

Answer:

(a).

$S_{n} = \frac{n}{2} (4n + 20) \\ \\S _{n - 1} = \frac{(n - 1)}{2} (4n - 4 + 20) \\ \\ S _{n - 1} = \frac{(n - 1)}{2} (4n + 16) \\ \\S _{n - 1} = \frac{(n - 1)(4n + 16)}{2} \\ \\ { \boxed{S _{n - 1} = {2 {n}^{2} + 6n - 8}}} \\$