Discuss why it helps to look at the frequency distribution for both groups in addition to the central tendency statistic in describing differences between the two groups

Yes it can cause that

It would have to be c or d

Which of the following is an example of an opposing signal? no examplthates given.   i would say, that traffic lights in a city at major intersections direct the flow of traffic in opposite directions so would be an example.also, stop signs on either side of the same street would be an example. at a train crossing, the light for allowing car traffic in opposite directions or not would be another example.