(a) Create a dummy variable using the AAC format as the baseline category (group) to represent the format of the song in the data file and then fit a regression model for how much space (in megabytes, MB) is needed to store a song based on the length of the song (Time in seconds). the format of the song, and the interaction of the format and the length of the song (Time in seconds). Write down the regression model including the estimates of the intercept and all slopes (round to three decimal places as needed). Based on the estimated intercept and slopes, (b) what is the fixed space (in megabytes) needed by songs recorded in the AAC format? (c) do songs recorded in the AIFF format need more or less fixed space (in megabytes) to get started than songs recorded in the AAC format? By how many megabytes? (d) how many megabytes per second do songs recorded in the AAC format take? (e) do songs recorded in the AIFF format need more or less space (in megabytes per second) than songs recorded in the AAC format? By how many megabytes per second? (f) Construct a prediction interval for the amount of disk space (in megabytes) required to store a song that is 250 seconds long using AAC and then AIFF format. The approximate 95% prediction interval for the AAC format is ( The approximate 95% prediction interval for the AIFF format is (