Question. Combine mean calculated by different given mean is ________?
  1. n1x1 + n2x2x + _____ nuxu/n1 +n2 + ___ + nu
  2. n1x1 + n2x2x + _____ nuxu/x1 + x2 + ____ x4
  3. n1x1 + n2x2x + _____ nuxu/n1 + n2 + ___+ nu
  4. ∑n1x/x1