a = {1.7610325845854935, 1.4482381483503182, 1.262594767165387, 2.2720460660207409};
b = {2.1844741151332943, 3.5175853047673318, 3.5245233201347768, 2.0819498353445609};
c = {1.3755036246747516, 1.6169073661736904, 2.3472569940481094, 2.9457474653314475};
dat = {a, b, c};
ListPlot[Table[Mean[dat[[i]]], {i, Length[dat]}],
    PlotStyle -> PointSize -> Large, PlotRange -> Full]

a = {1.7610325845854935, 1.4482381483503182, 1.262594767165387, 2.2720460660207409};
b = {2.1844741151332943, 3.5175853047673318, 3.5245233201347768, 2.0819498353445609};
c = {1.3755036246747516, 1.6169073661736904, 2.3472569940481094, 2.9457474653314475};
dat = {a, b, c};

Show[
 BoxWhiskerChart[dat, {"Mean", {"MedianMarker", None}}],
 ListLinePlot[Mean /@ dat, PlotRange -> Full]
 ]

BoxWhiskerChart[{a, b, c}, "Mean", Joined -> (Mean[#2] &), ChartStyle -> "Pastel"]

BoxWhiskerChart[{a, b, c}, "Mean", Joined -> (Mean[#2] &), ChartStyle -> "Pastel"] /.
  l : Line[__] :> {Red, Thick, l}

SeedRandom[1]
data = RandomVariate[NormalDistribution[], {10, 100}];

BoxWhiskerChart[data, "Mean", Joined -> (Mean[#2] &), ChartStyle -> "Pastel"] /.
  l : Line[__] :> {Red, Thick, l}