<span>In order to answer her question regarding how many students at her high school had summer jobs Nan must follow the procedure given in answer option B: First, randomly select 100 students, then ask them if they have summer jobs. In statistics this method is known as Population Sampling. These 100 students are chosen at random in order to avoid bias - we need them to be representative of the entire high school population.</span>
Explanation:
Given that,
Each vertical line on the graph is 1 millisecond (0.001 s) of time.
We need to find the period and the frequency of the sound wave. The period of a wave is equal to the each vertical line on graph i.e. 0.001 s.
Let f be the frequency of the sound wave. So,
f = 1/T
i.e.
So, the period and the frequency of the sound waves is 1 milliseond and 1000 Hz respectively.
Answer:
(a) You can tell that have the same strength because they have attracted the same amount of paper clips.
(b) Iron is used in electromagnets because steel retained magnetic properties after the power was turned off, but in the iron, the paper clips dropped off right away.
