A Study in Randomness
by Professor Rich Born
Figure 1 - Basic setup for the probability and statistics lab
The 17-second video below is an action shot of a portion of the data collection phase of this lab. In particular, notice the "peaks" produced when Voyager/intelino reach each of the magnets. The straight random choice shows negative peaks while the turn random choice shows positive peaks. This makes the data for the entire run easy (and fun!) to analyze.
Figure 2 contains an Excel chart of Voyager's magnetic field vs. time for a typical run of the experiment. This chart is a great visual that summarizes all events in the run. In this run, turns (T) are represented by positive peaks, and straights (S) are represented by negative peaks. We see that the experiment began with the intelino engine turning four times in a row, followed by one straight, followed by one turn, followed by two straights, and so on. If we represent a turn by the letter T and a straight by the letter S, we have the sequence of moves: TTTTSTSS... etc. Any unbroken sequence of like letters is referred to as a run. This is true even if the sequence has only one letter. In the sequence TTTTSTSS there are four runs: TTTT, S, T, and SS. The length of each of these runs (i.e., the number of letters in the run) is 4, 1, 1, and 2, respectively. The run lengths for the entire experiment are shown in red in Figure 2.
Figure 2 - Graph of x-magnetic field vs. time
Figure 3 - Track layout for activity 4