Both Mrs. Smith and Mrs. Jones had babies the same day in the same hospital. Mrs. Smith took home a baby girl named Shirley. Mrs. Jones took home a baby girl named Jane. Mrs. Jones began to suspect, however, that her baby had been accidently been switched with the Smith baby in the nursery. Blood tests were made. Mr. Smith was blood type A, Mrs. Smith was type B, Mr. Jones was type A, Mrs. Jones was type A. Shirley was type O, and Jane was type B. Had a mix-up occurred? SHOW WORK!

so if the babies were switched that means the blood test should make a correction

Explanation:

the answer is; comparing the frequency of collisions with and without the device

this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.