It means that there is a high chance that the child will think that the cup is red as well as a high chance that the child will think that the cup is blue. Here is one interpretation: If you show a blue cup and asked about its color, the child seems as likely to come up with red as blue because even I can't tell whether the color of that cup is blue or red. Here is another interpretation: If you show a blue cup and asked about its color, the child seems as likely to come up with red as blue because for some reason this child likes to say things are red even though tests have shown that the child is capable of differentiating between red and blue.

Tnx Jung

refer to " as ~as " equal comparison.

ممنون

means it has equal probability