Find the roots x2 + 4x + 5 = 0
2 answers:
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Answer:
a) X: number of years of education
b) Sample mean = 13.5, Sample standard deviation = 0.4
c) Sample mean = 13.5, Sample standard deviation = 0.2
d) Decrease the sample standard deviation
Step-by-step explanation:
We are given the following in the question:
Mean, μ = 13.5 years
Standard deviation,σ = 2.8 years
a) random variable X
X: number of years of education
Central limit theorem:
If large random samples are drawn from population with mean and standard deviation
, then the distribution of sample mean will be normally distributed with mean
and standard deviation
b) mean and the standard for a random sample of size 49
c) mean and the standard for a random sample of size 196
d) Effect of increasing n
As the sample size increases, the standard error that is the sample standard deviation decreases. Thus, quadrupling sample size will half the standard deviation.
Answer: There are 2346953264 ways to do so.
Step-by-step explanation:
Since we have given that
Total number of selected countries = 12
Number of selected countries from a block of 45 = 3
Number of selected countries from a block of 57 = 4
So, remaining number of selected countries from a block of 69.
So, 12-(3+4)=12-7=5
Now, we need to find the number of ways, so we will use "Combination" to select that number of countries.
So, it becomes.
Hence, there are 2346953264 ways to do so.