Astudent took the weighted average of the isotopes that make up one element. what was the
student trying to determine?

the atomic number of the element

the atomic mass of the element

the number of electrons in the element

the number of neutrons in the element

the atomic mass of the element

Explanation:

By taking the weighted averages of the different isotopes of an element, one can calculate the atomic mass of the element.

Using the process of mass spectrometry, one can simply determine the proportion/percentage/fraction by which each of the isotopes of an element occurs in nature. The proportion is called the geonormal abundance. We can then derive the atomic mass of an element which is the average mass of all the isotopes from this method.

             RAM = ∑mₓαₓ

where mₓ is the mass of isotope x

            αₓ is the abundance of isotope x

Harlowe school district.
A. The school should choose High School B since they have the least standard deviation among the three schools indicating that they have the least difference from the required number of school days and their actual number of school days attended.
B. The school should choose High School C since they have the highest mean indicating that they have the highest average attendance among other schools.

Car preferences. S - sedan; H - hatchbacks
A.
   a (like S & H) = 15; b (not like S, like hatchbacks) = 25; c (total people who like H) = 40
   d (not like H, like S) = 10; e (not like S & H) = 50; f (total people who don't like H) = 60
   g (total of those who like S) = 25; h (total of those who don't like S) = 75; i (total customers) = 100

B. Percentage of people who neither like S & H = 50%

C. Based on the summary of data, there are more dislikes for Sedan (75%) than Hatchbacks (60%)

Correlation. 
A. Yes, the correlation coefficient is -0.99... The data fit well in a line as the shown in the attached picture. 
B. y = -2.25x + 95.27
C. The slope indicates that every additional hour of browsing, the math score decreases. If a student doesn't spend time on the internet, he/she will get an average score of 95.27 in math.