Answer: Sample statistics are used to make inferences about population parameters.
Step-by-step explanation:
A number which describes a population is called a parameter, such as a proportion or percentage.
A statistic is a number which may be calculated from the data observed in a random sample without demanding the use of any unknown parameters.
The mean and variance of a population are population parameters.
Thus, fourth statement is the right answer "Sample statistics are used to make inferences about population parameters."
The y-intercept of the given table is 2000.
<u>Step-by-step explanation:</u>
Write the table in the ascending order.
From the table, calculate the rise and run to find the slope of the line.

Choose points (0,2000) and (1,1800).
rise= -200 and run=1.
Slope m = -200.
The line equation is y=mx+c.
Apply the slop value in the equation,
y= -200x+c.
To find the y-intercept substitute a value in the above equation.
Substitute(1,1800),
1800 = -200(1)+c.
2000=c.
y= -200x+2000.
The y-intercept is the point where the line passes through in the vertical y-axis at the origin.