Cоnsider the fоllоwing dаtа. Whаt is the grand mean? Please round to one decimal place. Failure to round correctly may result in your answer being marked wrong. Type of Seal Seal Strength Seal Strength Seal Strength Seal Strength Seal Strength Sample mean Sample SD 1 616.3 618.4 634.3 621.7 697.1 637.56 34.01 2 689.5 771.5 622.9 755.7 673.4 702.60 61.12 3 420.4 586.4 459.9 427.8 535.8 486.06 72.34 4 639.9 749.0 696.8 772.7 627.9 697.9 64.17