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

Q ,# 18 help to resolve please

Sati [7]

Answer: 120

"A analog clock is diveded up into 12 sectors, based on the numbers 1-12. one sector represents 30 degrees (360/12=30). if the hour hand is directly on the 10, and the minute hand is on the 2, that means there are 4 sectors of 30 degree between then, thus they are 120 degree apart (30*4=120)."

7 0

2 years ago

Solve the equation 9=m-4

Vedmedyk [2.9K]

9=m-4

9+4=m

13=m

9=13-4

9=9

I hope this answer helped you!!! Thank you!!!

4 0

2 years ago

Read 2 more answers

Five more than triple a number

Alexxandr [17]

Answer:

hope this helps

Step-by-step explanation:

five more: 5 +

three times the number q: 3q

Now put it together

7 0

2 years ago