For skewed distributions, such as the distribution of income for which a few people's incomes are substantially higher than most people's, the arithmetic mean may not coincide with one's notion of "middle".
fɔːɹ skjˈuːd dˌɪstɹɪbjˈuːʃənz, sˈʌtʃ ɐz ðə dˌɪstɹɪbjˈuːʃən ʌv ˈɪŋkʌm fɔːɹ wˌɪtʃ ɐ fjˈuː pˈiːpəlz ˈɪŋkʌmz ɑːɹ səbstˈænʃəli hˈaɪɚ ðɐn mˈoʊst pˈiːpəlz, ðɪ ɚɹˈɪθmətˌɪk mˈiːn mˈeɪ nˌɑːt kˌoʊɪnsˈaɪd wɪð wˈʌnz nˈoʊʃən ʌv "mˈɪdəl".