A teacher's first period class takes a math test and obtains a mean of 83 with a standard deviation of 5.6. The teacher's second period class takes the same test and obtains a mean of 74 with a standard deviation of 3.5. Considering a 90% confidence level, do the classes have significantly different means?

Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.