搜题请搜索小程序“爱下问搜题”
问题 解答题

甲乙两位同学在学校环形跑道上跑步，两人在同一地点往相反方向跑，甲每分钟跑52米，乙每分钟跑48米，4分钟后两人相遇，学校环形跑道是多少米？

答案

（52+48）×4

=100×4，

=400（米）．

答：学校环形跑道是400米．

单项选择题

假设检验的两类错误，以下说法哪一个对

A．Ⅰ型错误：拒绝实际上不成立的 H0

B．Ⅰ型错误的概率常用β表示

C．Ⅱ型错误是“弃真”的错误

D．Ⅱ型错误：不拒绝实际上不成立的H0

E．以上都不对
查看答案
单项选择题

In the following essay, each blank has four choices. Choose the most suitable one from the four choices and write down in the answer sheet. There are two types of key technology: private key and public key. Private-key encryption methods are called (71) ciphers, information is encrypted with (72) both the sender and receiver hold privately. Public-key encryption methods are called (73) ciphers, (74) created for each user, encryption key and decryption key are (75)

A．synchronous

B．Asynchronous

C．symmetric

D．asymmetric
查看答案