A) The question would be "Does cell phone use time correlate to brain cancer?". The population is all cell phone users. The sample is the 469 people with brain cancer, and the 422 healthy people.
B) This sample size may not portray the entire population of users because the positive results may have been fabricated by factors other than cell phone use. You would have to figure out the population size and determine the correct sample size.
C) This study may not portray cell phone use correlation over a large population efficiently because of the sample size and the predetermined conclusion that cell phone use causes cancer.
If by description you mean simplification then: 84x/28
The +k part of the function takes the original function and translates it straight up k units. It's as simple as that. If your function is the line f(x) = 3x, then the function f(x) = 3x + 4 moves that first function up 4 units.
The total amount Ellen paid for the book $16.21
Hope this helps!!