Recorded the mean math exam grade for six random samples of students from the entire seventh-grade class. sample sample mean grade 1 65 2 92 3 78 4 45 5 95 6 70 why is a valid prediction for the mean of the population not possible using these samples? a )fiona had too many samples. b )fiona didn’t have enough c )the variation of fiona’s samples is too large. d )the variation of fiona’s samples is too small.