Question

電腦鍵盤上的字母為何不按順序排列？請(qǐng)你來做一項(xiàng)統(tǒng)計(jì)，下面是一篇小短文，根據(jù)短文中字母a，b出現(xiàn)的機(jī)會(huì)完成后面提出的問題：
Two Trips
Jack brought a small plane and began to fly it． He soon became excited and made his plane all kinds of tricks．
Jack had a friend，named Tom． One day Jack said to him，“I will pick you up in my plane．““I will be glad to．'answered Tom． They went up，and Jack flew around for half an hour and did all kinds of tricks in the air． Then they came down． Tom was to be back safely，and said to Jack，“Well，Jack，thank you very much for those two trips in your plane．“Jack was very surprised and asked，“Two trips？““Yes，my first and my last．'an-swered Tom．
根據(jù)上文填表

出現(xiàn)字母的個(gè)數(shù)	100	150	200	250	300	350	400
出現(xiàn)字母a的頻數(shù)
出現(xiàn)字母a的頻率
出現(xiàn)字母b的頻數(shù)
出現(xiàn)字母b的頻率

Answer 1

解：如圖所示：

出現(xiàn)字母的個(gè)數(shù)	100	150	200	250	300	350	400
出現(xiàn)字母a的頻數(shù)	12	18	23	28	36	38	45
出現(xiàn)字母a的頻率	0.12	0.12	0.115	0.112	0.12	0.109	0.113
出現(xiàn)字母b的頻數(shù)	3	3	4	4	6	6	6
出現(xiàn)字母b的頻率	0.03	0.02	0.02	0.018	0.02	0.017	0.015

分析：根據(jù)頻數(shù)的概念及頻率的計(jì)算方法：頻率=求解．
點(diǎn)評(píng)：本題考查了頻數(shù)的概念及頻率的計(jì)算方法．
頻數(shù)是指每個(gè)對(duì)象出現(xiàn)的次數(shù)．
頻率是指每個(gè)對(duì)象出現(xiàn)的次數(shù)與總次數(shù)的比值（或者百分比）．即頻率=．