根据句短文理解，完成下列各题。
A group of people asked this question to a group 4-to-8-year-old children. “What does love mean?” The answers were surprising. The children would answer like they did below.
“When my grandmother hurt her knees (膝盖), she couldn't bent (弯腰) over and paint her toenails (脚指甲) any more. So my grandfather does it for her all the time, even when his hands hurt too. That's love.”
Rebecca–age 8
“Love is when someone hurts you. And you get so mad but you don't shout at them because you know it would hurt her feelings.”
Samantha–age 6
“Love is what makes you smile when you're tired.”
Terri–age 4
“I let my big sister pick on (捉弄) me because my mum says she only picks on me because she loves me. So I pick on my baby sister because I love her.”
Bethany–age 4
“I know my older sister loves me because she gives me all her old clothes and has to go out and buy new clothes.”
Lauren–age 4
“Love is when Mommy gives Daddy the best piece of chicken.”
Elaine–age 5
“My mommy loves me more than anybody. You don’t see anyone else kissing me to sleep at night.”
Clear–age 5
“You really shouldn't say ‘I love you’ unless you mean it. But if you mean it, you should say it a lot. People forget.”
Jessica–age 8
是幂函数；
来刻画回归效果，
服从正态分布N（0，1），若
，则
；