If [img=114x23]1803dc1abbcac9d.png[/img] is a sample of normal population N([img=36x26]1803dc1ac53b272.png[/img]), and [img=15x22]1803dc1acde7709.png[/img] and [img=19x22]1803dc1ad5f413c.png[/img] are the sample mean and sample variance, then [img=15x22]1803dc1acde7709.png[/img] and S are independent of each other.
举一反三
- Let's say that population X~N（[img=36x26]1803dc1a509e5ed.png[/img]）,[img=114x23]1803dc1a594f2d6.png[/img] is the sample of X,[img=15x22]1803dc1a6159fd0.png[/img] is the mean of our sample, and [img=19x22]1803dc1a69f6423.png[/img] is the variance of our sample.Which of the following is not true? A: [img=190x74]1803dc1a75634cd.png[/img] B: [img=118x46]1803dc1a7e668c3.png[/img] C: [img=135x50]1803dc1a8a7f9af.png[/img] D: [img=153x72]1803dc1a9526716.png[/img]
- Suppose population X~N([img=11x18]1803dc19edf699d.png[/img],4), where [img=11x18]1803dc19f88e314.png[/img] is unknown, [img=128x25]1803dc1a0221cf9.png[/img] is the sample from the population, the sample mean is [img=15x22]1803dc1a0acf7b5.png[/img], and the sample variance is [img=16x22]1803dc1a13743b1.png[/img], then the non-statistic of the following is A: 2[img=15x22]1803dc1a1c346e6.png[/img] B: [img=18x46]1803dc1a2464660.png[/img] C: [img=48x48]1803dc1a2d89174.png[/img] D: [img=72x46]1803dc1a36d6cae.png[/img]
- If [img=128x25]1803dc19dbe2211.png[/img] is the sample of population N(1,4) and [img=15x22]1803dc19e50d7ff.png[/img] is the sample mean, which of the following conclusions is true? A: [img=94x50]1803dc19ee1df1e.png[/img] B: [img=179x59]1803dc19fa74975.png[/img] C: [img=136x52]1803dc1a067981e.png[/img] D: [img=160x59]1803dc1a11fc728.png[/img]
- 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.
- 1.设随机变量X的密度为[img=186x61]18034ea953ec9dd.png[/img]则常数A=________，概率[img=146x25]18034ea95d30d08.png[/img]__________. A: A=2，P(X>1|X<2)=[img=39x24]18034ea9659b618.png[/img] B: A=-2，P(X>1|X<2)=[img=39x24]18034ea9659b618.png[/img] C: A=2，P(X>1|X<2)=[img=47x44]18034ea9768a8c2.png[/img] D: A=-2，P(X>1|X<2)=[img=47x44]18034ea9768a8c2.png[/img]