一个样本的容量是80,分成若干小组画频数分布直方图,某组对应的频率是0.2,则该组有______个数据.
依题意,得该组数据=80×0.2=16,
故答案为:16.
关于氨基酰-tRNA合成酶的特点正确的是()
A.催化的反应需要GTP供能
B.可以水解酯键校正氨基酸和tRNA之间的错配
C.只对氨基酸有绝对专一性
D.只对tRNA有绝对专一性
E.总共有20种酶分别催化20种氨基酸和对应的tRNA的连接
After you activate your emergency position indicating radiobeacon,you should().
A.turn it off for five minutes every half-hour
B.turn it off and on at five-minute intervals
C.turn it off during daylight hours
D.leave it on continuously