3) A student studying the sleeping habits of seniors at his school asked 36 randomly-selected seniors how many hours of sleep they got the previous night. The data, rounded to the nearest half-hour, is given in the table below. 8 7.5 9 7.5 9 6 5 9 7.5 7 8 7 6.5 8.5 8 6.5 8.5 7 7.5 7 6 8.5 7 7 8 7 7.5 7 6 7 8 7.5 6 7 5 a) Using your calculator, find the mean and median of this data. Without graphing it, what shape do you suspect, give the values of the mean and median? b) Find and interpret the standard deviation. c) Suppose 4 more values were added to the data, each exactly equal to the mean. Would this have any impact on the standard deviation? Explain, without using any calculations