A study of a local high school tried to determine the mean number of text messages that each student sent per day. The study surveyed a random sample of 70 students in the high school and found a mean of 161 messages sent per day with a standard deviation of 68 messages. Determine a 95% confidence interval for the mean,

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.