Sine the last number (3) is less than 5 it is rounded to 257.67
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:
B , D , A ,C
Step-by-step explanation:
PEMDAS
Go up on the graph (y axis) and you need to go down 3 on the y axis and go to the right one and repeat. let me know if you want me to draw it out!