Ineed with my homework. i don’t get it

Two lines that do not intersect are skew. always sometimes or never

An automated water dispenser fills packets with one liter of water on average, with a standard deviation of 5 milliliter. the manual says that after a year of operation the dispenser should be tested to see if it needs recalibration. a year later a number of filled packets are set aside and measured separately. it is found that the average packet now contains about 0.995 liters. does the dispenser need calibration? explain your answer.

Which type of graph would allow us to quickly see how many students between 100 and 200 students were treated?