A: must be very large
B: must have a normal distribution
C: can have any distribution
D: must have a mean of at least 1
举一反三
- For any normal distribution, any value less than the mean would have a _______.
- 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.
- The normal approximation to the binomial distribution works best when the number of trials is large, and when the binomial distribution is symmetrical (like the normal).
- In determining an interval estimate of a population mean when σ is unknown, we use a t distribution with n - 1 degrees of freedom.
- A standard normal distribution is a normal distribution with:
内容
- 0
As a general rule, the normal distribution is used to approximate the sampling distribution of the sample mean only if
- 1
You when you heard the news。 A: must be very excited B: must have been very excited C: can be very excited D: will have been very excited
- 2
“____ he have left yesterday?” Yes, he ____<br/>yesterday.” No, he ____ yesterday.” A: Must; must have left; can’t have left B: Can; can have<br/>left; can’t have left C: Can; must have left; can’t have left D: May; must<br/>have left; shouldn’t have left
- 3
4. Sounds in complementary distribution must be allophones.
- 4
Where ________ Mary have put the empty bottles? -She ________ them away. They must be somewhere. A: can; can't have thrown B: must; needn't C: must; must have thrown D: can; mustn't have thrown