When the sample sizes are equal, the pooled variance of the two groups is the average of the two sample variances.

When temperature is higher than melting point, ( ) affect(s) water activity. A: sample composition B: sample weight C: sample color D: temperature

2. When do Ruth and Bill plan to Hong Kong for vacation (Sample 1)?

If n samples are extracted from any population with mean value [img=11x18]1803dc1a4012523.png[/img] and variance [img=18x22]1803dc1a48a9511.png[/img], then A: When n is sufficiently large, the distribution of sample mean is approximately normal distribution. B: When n<10, the distribution of sample mean is approximately normal distribution. C: The distribution of sample mean is nothing to do with n. D: No matter how big n is, the distribution of the sample mean is not going to be close to a normal distribution.

To compute an interval estimate for the difference between the means of two populations, the t distribution __ A: is restricted to small sample situations. B: is not restricted to small sample situations. C: can be applied when the populations have equal means. D: can be applied only when the populations have equal standard deviations.

When a person draws a conclusion about a population based on a sample that is not large enough, the person is likely to commit a fallacy called:

Counter sample can also be called ( ) A: duplicate sample B: sealed sample C: return sample D: reference sample

15. When describe the quality of the commodity, people usually use 3 ways: sale by sample, sale by descriptions and sale by actual quality.

When the size of the sample is between 0.1-10mg, the analysis is called: A: major analysis B: minor analysis C: trace analysis D: self-minor analysis

Counter<br/>sample can also be called _____________.() A: duplicate<br/>sample B: sealed<br/>sample C: confirmed<br/>sample D: contracted<br/>sample