9. Given A = {1, 2, 3, 4, 5, 6, 7, 8, 9} and B = {2, 4, 6, 8}, what is A∪B?
PtichkaEL [24]
A union B is the set containing all elements in set A and set B there for A union B is the set {1 2 3 4 5 6 7 8 9}
Answer:
Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:
Where
and
And for this case we select a sample size of n= 81. Since the distribution for X is normal then we know that the distribution for the sample mean
is given by:
And the standard error of the mean would be:

4.1.5
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:
Where
and
And for this case we select a sample size of n= 81. Since the distribution for X is normal then we know that the distribution for the sample mean
is given by:
And the standard error of the mean would be:

4.1.5
Answer:
a+b = 4
Step-by-step explanation:
3(a + b)^2 = 81
(a + b)^2 = 27
a + b = sq rt 27
a + b =
· 
a + b = 3