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

The margin of error of the interval is:

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

90% confidence level

So $\alpha = 0.1$ , z is the value of Z that has a pvalue of $1 - \frac{0.1}{2} = 0.95$ , so $Z = 1.645$ .

How large of a sample must she have to get a margin of error less than 0.03

We need a sample of at least n students.

n is found when M = 0.03.

We have no information about the true proportion, so we use $\pi = 0.5$ .

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

$0.03 = 1.645\sqrt{\frac{0.5*0.5}{n}}$

$0.03\sqrt{n} = 1.645*0.5$

$\sqrt{n} = \frac{1.645*0.5}{0.03}$

$(\sqrt{n})^{2} = (\frac{1.645*0.5}{0.03})^{2}$

$n = 751.67$

Rounding up

We need a sample of at least 752 students.

6 0

4 years ago

PLEASE HELP!!

vagabundo [1.1K]

C. 180 feet.

If the player stands on the 2nd base then hes only like two bases to the Home plate (3rd and Home plate)

so each base is 90 degrees.

90+90 (3rd base + Home plate)

= 180 feet.

Hope this helps.

4 0

3 years ago

Write the first three multiples of each number 6,11,14

hoa [83]

6,12,24,30,36,42,

11,22,33,44,55,66

14,28,42,56,70,84

7 0

3 years ago

I just need brainliest please

RideAnS [48]

Answer:

alright if you give me brianliest on this, when you answer one of my questions ill give you brainliest. brailiest for a brianliest?

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

A computer store bought a program at a cost of ​$ and sold it at a selling price of ​$. Find the percent markup.

A computer store bought a program at a cost of $ and sold it at a selling price of $. Find the percent markup.