Answer: 18
Step-by-step explanation:
- The<u> sample mean</u> is the best point estimate of the population mean .
Given : A simple random sample of 5 observations from a population containing 400 elements was taken, and the following values were obtained (12 18 19 20 21).
Then , the sample mean = 
sample mean 
Hence, A point estimate of the mean is 18.
Answer:
D. y = 2x² + 1
E. y = x²
Step-by-step explanation:
Linear function:
A linear function has the following format:

In which a is the slope and b is the y-intercept. A constant function is linear, as it is the special case in which a = 0.
In this question:
In options D and E, the highest exponent of x is 2, which means that they are not linear functions, and so these options are the answer.
Answer:
Step-by-step explanation: the first is m the second one is 15x+5
Answer:
The first listed equation is the correct equation to solve
The correct answer is: t = 5 seconds
Step-by-step explanation:
Let me mention first that there is an error in the statement that the gravitational pull of the Earth is 16 ft/s^2. It is in fact 32 ft/s^2, and the actual equation uses half of the acceleration multiplied by the square of the variable time, so it gives as final expression :

and we want to find the value/s for "t" that make this equation equal zero (when it reaches the ground and the object just touches the ground. This makes the equation we want to solve:

which solving for "t" becomes:

So we adopt the positive answer (positive time) since the negative value has no physical meaning for this problem.
That is: t = 5 seconds