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

Recognize functions from graphs, yes or no

never [62]

Answer:

If your asking whether the graph shown is a function or not the answer is yes it is a function.

Step-by-step explanation:

There is a test called the vertical line test that states if you can draw a vertical line anywhere on the graph and it only passes through one point then the graph represents a function.

3 0

3 years ago

Wang Yong owes the bank $8500. To repay the debt, he paid a fixed amount back to the bank each month. After 12 months, his remai

-Dominant- [34]

Answer:

"How much did Wang Yong pay each month" answer: $170

"How long did it take Wang Yong to pay back his entire debt?" answer: 50 months

5 0

3 years ago