μ and [img=18x22]17de81fccbbd283.png[/img] are the two parameters for a normal distribution. In which situation the curve of probability density function of a normal distribution will become narrow?
A: When μ becomes larger.
B: When μ becomes smaller.
C: When σ becomes larger.
D: When σ becomes smaller.
E: When μ and σ both become larger.
A: When μ becomes larger.
B: When μ becomes smaller.
C: When σ becomes larger.
D: When σ becomes smaller.
E: When μ and σ both become larger.
举一反三
- 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.
- When bonds become more widely traded, and as a consequence the market becomes more liquid, the demand curve for bonds shifts to the _________ and the interest rate _________.
- When did the third green wave come A: When environmental concern rises. B: When advertisers are self-regulating themselves. C: When advertisements become very regulated. D: When the mainstream also becomes concerned about it.
- 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).
- 1) What happens to the magnitude of the magnetic field inside a long solenoid if the current is doubled? A: It becomes four times larger. B: It becomes twice as large. C: It is unchanged. D: It becomes one-half as large. E: It becomes one-fourth as large.