Premise: "Someone is whisking eggs with a handheld mixer."
Hypothesis: "The chef believes hand mixing is the only proper way."
Do we know that the hypothesis entailed by the premise? Now, let's be accurate as possible. Some thinking first:
A person whisking eggs is not necessarily a chef. People of all walks of life can whisk eggs. Just because someone is whisking with a handheld mixer is doesn't imply that he or she believes hand mixing in the only proper way. The person could be mixing that way because the electricity is out or simply because it is the way he or she has always done it. So, the answer is it is not possible to tell.