A bank is trying to determine which model of safe to install. The bank manager believes that each model is equally resistant to safe crackers but sets up a test to be sure. He hires nine safe experts to break into each of the models, timing each endeavor. The results (in seconds) are given next, paired by expert. Let D be the difference: Time to break Safe 1 minus Time to break Safe 2. Safe 1 Safe 2 103 101 90 94 64 58 120 112 104 103 92 90 145 140 106 110 76 74 Should we conclude that the average time it takes experts to crack the safes does not differ by model at the 5% significance level?

proportions are fractions that equal to each other. so if two fractions are the same, they are proportional.

let's check the answers to see if they are proportional.

question a is not proportional because you can't turn 1.5/3 to 3/9. if you try to multiply 1.5/3 by 2 or 3, you wont get 3/9. it's impossible to make the fractions the same.

question b is not proportional because you can't turn 22/33 to 4/6. 33 can't go into 6.

question c is proportional because when you multiply 2 and 3 by 71, you would get 142/213, and those fractions equal to each other

question d is proportional because when you divide 14 and 7 by 2, you would end up with 7/3.5, and those fractions equal to each other.

the answer is 0052

0 0 5 2

5 0 2 6 3 5

− 0

2 6

− 0

2 6 3

− 2 5 0

1 3 5

− 1 0 0

3 5

c.

step-by-step explanation: it's not a. because 1/3 x 1/3 x 1/3 = 1/27 so that's not correct. | b. is also not correct because 7 x 7 1/3 is not actually 3 x 7 1/3 . and for d. multiplications are not additions so that left you with c. ( hope this out : d )