In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence interval $1-\alpha$ , 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 is:

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

95% confidence interval

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

In this problem, we have that:

$p = 0.5, M = 0.1$

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

$0.1 = 1.96*\sqrt{\frac{0.5*0.5}{n}}$

$0.1\sqrt{n} = 0.98$

$\sqrt{n} = 9.8$

$(\sqrt{n})^{2} = (9.8)^{2}$

$n = 96$

The minimum number of cities we need to contact is 96.

8 0

2 years ago

The Students at Sunnyside School built a rectangular pyramid of aluminum cans for a world record. The top layer had 2 rows with

Lana71 [14]

2 times 3 equals 6.and 4 times6 equals 24.and 8 times 12 equals 96 add them all together and you will get 126

HOPE THIS HELPS
If it does please press the heart thing please

7 0

3 years ago

Compared to an exponential function y = b where b > 0, a quadratic function grows: slower faster at the same rate sometimes f

Verizon [17]

Answer:

it's slower babe

6 0

3 years ago

6.9•10 to the fourth power divided by 6.6•10 to the negative 5

e-lub [12.9K]

23/200
...............

3 0

2 years ago

I need help with this one please..​

I need help with this one please..