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 $1 - \frac{\alpha}{2}$ .

Of the 2809 people who responded to survey, 1634 stated that they currently use social media.

This means that $n = 2809, \pi = \frac{1634}{2809} = 0.5817$

98% confidence level

So $\alpha = 0.02$ , z is the value of Z that has a pvalue of $1 - \frac{0.02}{2} = 0.99$ , so $Z = 2.327$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.5817 - 2.327\sqrt{\frac{0.5817*4183}{2809}} = 0.56$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.5817 + 2.327\sqrt{\frac{0.5817*4183}{2809}} = 0.6034$

The 98% confidence interval estimate of the proportion of adults who use social media is (0.56, 0.6034).

6 0

2 years ago

How do I get the answer??

Lubov Fominskaja [6]

Answer:

4√10

Step-by-step explanation:

Hello!

Let's first simplify the radical.

We can do this by expanding the radical:

We need to pull out a perfect square factor to expand a radical and simplify it. In 45, we have 9 and 5 multiplied, and 9 is a perfect square.

Let's work with √45:

√45 can be written as √9 * √5 (using the rule √ab = √a * √b)
√9 simplifies to 3, so it is 3√5

Now we can simplify the operation in the parenthesis by combining like terms:

3√5 + √5
√5 + √5 + √5 + √5
4√5

Now using the same rule as above, we can multiply the values:

√2(4√5)
4√10

Your solution is 4√10

3 0

2 years ago