Answer:
The approximate standard deviation of the sampling distribution of the mean for all samples of size n is ![s = \frac{\sigma}{\sqrt{n}} = \frac{21}{\sqrt{n}}](https://tex.z-dn.net/?f=s%20%3D%20%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D%20%3D%20%5Cfrac%7B21%7D%7B%5Csqrt%7Bn%7D%7D)
Step-by-step explanation:
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean
and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
The mean life expectancy of a certain type of light bulb is 945 hours with a standard deviation of 21 hours
This means that
.
What is the approximate standard deviation of the sampling distribution of the mean for all samples of size n?
![s = \frac{\sigma}{\sqrt{n}} = \frac{21}{\sqrt{n}}](https://tex.z-dn.net/?f=s%20%3D%20%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D%20%3D%20%5Cfrac%7B21%7D%7B%5Csqrt%7Bn%7D%7D)
The approximate standard deviation of the sampling distribution of the mean for all samples of size n is ![s = \frac{\sigma}{\sqrt{n}} = \frac{21}{\sqrt{n}}](https://tex.z-dn.net/?f=s%20%3D%20%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D%20%3D%20%5Cfrac%7B21%7D%7B%5Csqrt%7Bn%7D%7D)
4d = 1/3
d = 1/3/4
d = 1/12
Thus, c is the correct choice.
Answer:
2bd
Step-by-step explanation:
Answer:
There are 16276 different stocks which are possible to uniquely designate with these codes
Step-by-step explanation:
The information we have is that
1. There are 26 different letters.
2. The stock can be designated with a one, two or three letter code and the letters may be repeated (We always have 26 options for the first, second and third letter)
3. Order matters (different order constitute a different code), which means we're talking about permutations.
The total codes we can make would be:
![P_{26|1} + P_{26|2}+ P_{26|3} \\26+650+15600= 16276](https://tex.z-dn.net/?f=P_%7B26%7C1%7D%20%2B%20P_%7B26%7C2%7D%2B%20P_%7B26%7C3%7D%20%20%20%5C%5C26%2B650%2B15600%3D%2016276)