Answer:
Let X the random variable that represent the heights of a population, and for this case we know the distribution for X is given by:
Where
and
Since the distribution for X is normal then the we know that the distribution for the sample mean
is given by:
And the standard error is given by:

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 heights of a population, and for this case we know the distribution for X is given by:
Where
and
Since the distribution for X is normal then the we know that the distribution for the sample mean
is given by:
And the standard error is given by:

4.5 miles is equal to 7920 yards
Answer:
A. choosing a sock from a drawer, putting it on, then picking another sock from the drawer
Given:
pi is equal to 3.14
3.14 ÷ 2/3
Rules in dividing fractions.
3.14 is the 1st fraction. It has a denominator of 1. 3.14/1
2/3 is the 2nd fraction
1) get the reciprocal of the 2nd fraction.
2/3 ⇒ 3/2
2) multiply the 1st fraction to the reciprocal of the 2nd fraction
3.14 * 3/2 = (3.14*3) / 2 = 9.42 / 2 = 4.71
Pi divided by 2/3 is 4.71