In the text before the start of the first, to an arithmetic question it. Conditions 1-a person to the number of students in statistics, sampled a some primary school within the 500 students, random spot check; The men and women get ratio is the USA.
Condition 2-from school file to understand, at present the school boys were 400.
Question 1: this school about how many students are there altogether?
Question 2: how many girls?
Question 3: how many people are only children, how many are not?
If simple point to, the first two asked is actually a primary school in arithmetic. Total students is 400/55% * 100% = 727 (number, take integer), total girl is 727-400 = 327. The third asked is pure 2 B, don't explain, god knows how many. (if deep into the principles of statistics on consideration, the randomness, and 1 conditions is the 500 samples is in accordance with the statistics requirements will become very important. If this random is not entirely in the sense of random distribution, the result may deviation, but the deviation of range have how old? In a total of 727 sample space is in 57 500 samples, 68.8% coverage, hobbies, and remember to ask investigation of the high number of knowledge for let students deviation.)
7.27 million iPhone, 3.27 million is unicom. There are many gray, and how much of the problem of HangHuo as the above problem 3, root no relation, known conditions and the no any relation! Meanwhile, more than 700 iPhone just last month, the number and GMIC simultaneously on XiongJun CEO network data released by the agreement.