A professor wants to conduct a study to know whether the grades she gives to her students affect their evaluations of her. She teaches four classes of ten students each. She has a theory that the grades and her evaluations are affected by the following characteristics of students:

A student's gender
A student's age
The hours of sleep a student gets per night
A student's year in the college
A student's current grade
The number of pets a student owns

Identify the independent and dependent variables in this study. For the independent variables, explain what can be the possible levels (subcategories within each variable) of the variables or the range of values.

Explain the relationship between the sample and the population in the study.

Identify the scales of measurement (nominal, ordinal, interval, and ratio) for each of the variables. Explain why the scale of measurement you chose is appropriate for this study. Some variables have more than one possible scale of measurement; so support your reasoning with examples.

In one of the professor's classes, students' evaluations of her (scored on a scale of 1 to 10) are as follows: 3, 5, 5, 5, 5, 6, 6, 8, 8, and 9. For these evaluations:

Calculate (ΣX)/n.

The university changes its scoring policy, and now the students' evaluations are scored on a scale of 5 to 15. For these evaluations:

Calculate (Σ(X + 5))/n.

The professor wants to see what would happen if each student gives her one point higher. Describe the formula to calculate that.