“…2 will be the low-middle impression based on the mode of three users' PI X , namely, low-middle, middle, and low-middle. However, when there is more than one mode of PI X in the song, the CI is defined as (1) where CI is rounded half up to the nearest whole number; PI X is set to the values; that is, low is 5, low-middle is 4, middle is 3, middle-high is 2, and high is 1, for each impression; n is the number of users who answered PI X for the song. For example, as shown in Table 1, the CI of song No.…”