Data regarding average reported number of calories consumed per day is collected from a random sample of 800 CSUN students chosen using randomly selected student ID numbers. The mean reported number of calories consumed per day from the sample is found to be 2,700. What is the best estimate for the unknown population average reported number of calories consumed per day of all CSUN students?

The best estimate for the unknown population average reported number of calories consumed per day of all CSUN students is the sample mean, 2700.

Step-by-step explanation:

A parameter is a characteristic of a population. It is a numerical value of the population characteristic. It is based on all the population values.

A statistic is a characteristic of a sample. It is a numerical value of the sample characteristic. It is based on all the sample values drawn from the population.

A sample statistic is an unbiased estimator of the population parameter.

The sample statistic is also known as the point estimate of the parameter value.

The sample mean is a sample statistic.

So the sample mean is a point estimate of the population mean.

In this case the sample mean number of calories consumed per day computed using a sample of 800 CSUN students is 2,700.

Then the best estimate for the population mean number of calories consumed per day by all CSUN students is, .

Thus, the best estimate for the unknown population average reported number of calories consumed per day of all CSUN students is the sample mean, 2700.

The square root of a a negative integer is imaginary.
It would still be a negative under a square root if you multiplied it by 2, therefor it will still be imaginary, or I’m assuming as your book calls it, undefined.
2•(sqrt-1) = 2sqrt-1

If you add a number to -1 itself, specifically 1 or greater it will become a positive number or 0 assuming you just add 1. In that case it would be defined.
-1 + 1 = 0
-1 + 2 = 1

If you add a number to the entire thing “sqrt-1” it will not be defined.
(sqrt-1) + 1 = 1+ (sqrt-1)

If you subtract a number it will still have a negative under a square root, meaning it would be undefined.
(sqrt-1) + 1 = 1 + (sqrt-1)

however if you subtract a negative number from -1 itself, you end up getting a positive number or zero. (Subtracting a negative number is adding because the negative signs cancel out).
-1 - -1 = 0
-1 - -2 = 1

If you squared it you would get -1, which is defined
sqrt-1 • sqrt-1 = -1

and if you cubed it, you would get a negative under a square root again, therefor it would be undefined.
sqrt-1 • sqrt-1 • sqrt-1 = -1 • sqrt-1 = -1(sqrt-1)

Sorry if this answer is confusing, I don’t have a scientific keyboard, I’ll get one soon.