Answer:
Yes, this is a valid inference because she took a random sample of the neighborhood.
Step-by-step explanation:
As we can see, Sue's survey was perfectly random and without any prejudice.
18% of the families, according to her research, would volunteer at the shelter. According to her, 18% of the local households should be required to volunteer at the animal shelter.
Therefore, given that she chose a representative sample of the area, her conclusion is valid.
Answer:
B. 
D. 
Step-by-step explanation:
Given:
The inequality for 'x' is given as:

The above inequality tells us that, the value of the variable 'x' is less than -200.
-200 is a negative number. So, for a negative number, the larger the value of the number, the smaller the number is.
Example: -2 is less than -1 although 2 has a greater magnitude than 1.
Therefore, the numbers that are less than -200 are -210 and -201.
So, the values of 'x' that satisfy the given inequality are -201 and -210
Thus, the correct options are (B) and (D).
Answer:

And we can solve this using the following z score formula:

And if we use this formula we got:

So we can find this probability equivalently like this:

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
We select n =100. Since the distribution for X is normal then we know that the distribution for the sample mean
is given by:
We want this probability:

And we can solve this using the following z score formula:

And if we use this formula we got:

So we can find this probability equivalently like this:

Answer the answer is 76.6
Step-by-step explanation: