The 95% confidence interval for the fraction of all shoppers during the year whose visit was because of a coupon they'd received in the mail is (0.2016, 0.2694).

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 z-score that has a p-value of $1 - \frac{\alpha}{2}$ .

A store randomly samples 603 shoppers over the course of a year and finds that 142 of them made their visit because of a coupon they'd received in the mail.

This means that $n = 603, \pi = \frac{142}{603} = 0.2355$

95% confidence level

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

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.2355 - 1.96\sqrt{\frac{0.2355*0.7645}{603}} = 0.2016$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.2355 + 1.96\sqrt{\frac{0.2355*0.7645}{603}} = 0.2694$

The 95% confidence interval for the fraction of all shoppers during the year whose visit was because of a coupon they'd received in the mail is (0.2016, 0.2694).

8 0

2 years ago

Y=23x y=-x+5y=−x+5 pls help

irina1246 [14]

Sorry only doing this for points

5 0

2 years ago

Is the simplified form of 2-3 + 3.3 rational?<br> Yes<br> No

N76 [4]

Answer:

YES IT IS

Step-by-step explanation:

2-3 + 3.3

= -1 + 3.3

= -4.3

We learn that:

Rational number: rational number is the number that can be written as a/b (a and b would be intergers and b is not equal to 0). Rational number would be most of numbers we use in out life, except Square root and Pi number.

In this case, -4.3 can be write as -43/10

So YES it would be a rational number

Hope this helped :3

6 0

3 years ago

This year 426,731 people visited a water park.last year 102,865 fewer people visited the park the year the park opened 84,007 fe

mylen [45]

Answer:

236,859 people visited the water park the year it opened.

Step-by-step explanation:

426,731 - 102,865= 323,866 the amount of people that visited last year

323,866 - 87,007 = 236,859 the amount of people that visited the water park the year it opened

7 0

3 years ago