4) A spring modeling a sinusoidal function rests 1.6 meters above the ground. If the mass on the spring is pulled 1.1 meters below its resting positions and then released, it requires 0,5
seconds to move from the minimum positions to its maximum positions. Assuming friction
and air resistance are neglected,
Write an equation in terms of cosine that describes this periodic function.

You are in charge of the customer service phone line with many employees. at the end of each phone callthe customers are asked to rate their service from 1 to 5 stars, with 5 being the best. you find the averagerating for 20 randomly selected employees and decide you want to improve the ratings so you require thoseemployees to go through a new training program. you then wait a week and find the new average rating foreach employee. the average change is an increase in 1.3 stars with a standard devation of .9 stars.(a) is this data paired or not paired? (b) what are the null and alternative hypothesis being tested? (c) what is the t-statistic you would use? write the general formula and the final calculation.(d) sketch a t-distribution, label your t-statistic and the probability you would be interested in: