Which are the common used ways to sampling? A: Simple random sample without replacement B: Simple random sample with replacement C: Stratified sample D: Cluster sample

A researcher wants to estimate the difference in the means of two populations. A random sample of 36 items from the first population results in a sample mean of 430. A random sample of 49 items from t

中国大学MOOC: random库的 random.sample(pop，k)函数的作用是（）。

A sample in which the characteristics of the sample are the same as those of the population is a(n): （ ） A: attributes sample. B: variables sample. C: random sample. D: representative sample.

假设random模块已导入，那么表达式 random.sample(range(10), 7) 的作用是生成7个不重复的整数

Regarding the sample average and the population average, the following is correct ( ) A: Both are random variables B: Both are definite values C: The former is a certain value and the latter is a random variable D: The former is a random variable and the latter is a certain value

The<br/>process which requires the calculation of an interval and then<br/>selects the items based on the size of the interval is ( <br/>) A: statistical<br/>sampling. B: random<br/>sample selection. C: systematic<br/>sample selection. D: computerized<br/>sample selection.

A<br/>sample in which the characteristics of the sample are the same as<br/>those of the population is a ( ) A: variables<br/>sample. B: representative<br/>sample. C: attributes<br/>sample. D: random<br/>sample.

已知seq为长度大于10的列表，并且已导入random模块，那么[random.choice(seq)foriinrange(10)]和random.sample(seq,10)等价。

The survey used a ______ sample of two thousand people across the Midwest. A: random B: relaxed C: relieved D: reluctant