A survey of 9 retirees was taken. Among other things, the retirees were asked to report the age at which they retired. Here are those 9 ages (in years). 55, 74, 66, 66, 74, 66, 67, 57, 74 Send data to calculator (a) What is the median of this data set? If your answer is not an integer, round your answer to one decimal place. (b) What is the mean of this data set? If your answer is not an integer, round your answer to one decimal place. (c) How many modes does the data set have, and what are their values? Indicate the number of modes by clicking in the appropriate circle, and then indicate the value(s) of the mode(s), if applicable. 0 0 zero modes one mode: two modes: and