Answer:
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 
, and a confidence level of 
, we have the following confidence interval of proportions.
In which
z is the z-score that has a p-value of 
.
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 
95% confidence level
So 
, z is the value of Z that has a p-value of 
, so 
.
The lower limit of this interval is:
The upper limit of this interval is:
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).
X+3y=7
x-3y=1
add them together
x+3y=7
<u>x-3y=1 +
</u>2x+0y=8
2x=8
divide 2
x=4
subsitute
x+3y=7
4+3y=7
subtract 4
3y=3
divid 3
y=1
x=4
y=1
answer is A
<u />
Answer:
1/4, 0.25
Step-by-step explanation:
The reciprocal of a number is 1 divided by the number. 1/4=0.25.
Answer:
n= 1/2 ( 
) or (0.5)
AND
n= -3/2 ( 
) or (-1.5)
Step-by-step explanation:
4n^2+4n=3
step1: move 3 to the other side and make the equation equal to zero.
4n^2+4n-3=0
step2: factorise the equation.
(2n-1)(2n+3)=0
step3: make each bracket equal to zero.
2n-1=0
2n+3=0
step4: solve for n values.
<u>1.</u> 2n-1=0
(add 1 for both sides)
2n=1
(divide by 2 for both sides)
n= 1/2 ( ) or (0.5)
<u>2.</u> 2n+3=0
( subtract 3 for both sides)
2n=-3
(divide by 2 for both sides)
n= -3/2 ( ) or (-1.5)
