Three high school participated in a study to evaluate the effectiveness of a new computer-based mathematics curriculum. Four 24-student sections of freshman algebra were available for the study. The two types of instruction (standard curriculum, computer-based curriculum) were randomly assigned to the four sections in each of the three schools. At the end of the term, a standard mathematics achievement test was given to each of the 24 students in each section. a. Is this study experimental, observational, or mixed experimental and observational? Why?
b. Identify important factors, factor levels, and/or factor-level combinations.
c. Classify these factors as within- or between-subjects
d. what’s the dependent measures?
e. What is the basic experiment unit of study?

Given that;

There are three high schools, each having four sections of every 24 students

the 2 types of instructions are Standard curriculum  & computer based curriculum

a)

this study is experimental

this is because the study did not just observe the student's performance but randomly assign the performance to different techniques that have some certain control over the technique of teaching and then observe their performance afterwards

b)

-important  factors are; high schools, instruction type and scores

- Highschool has 2 levels: level one there are three high schools,  level 2 each having four sections of every 24 students

-instruction type: has one level which is  divided into two namely; standard base and computer based

Scores: doesn't have levels

c)

there are 3 schools and 4 sections  so the factor high school has between subjects components

factor instruction type also has between subjects because there are two different types available

there are 24 students in each section which are within subjects

d)

the score on the test  is the dependent measures

e)

“STUDENT” in each section is he basic experiment unit of study

the answer is: d) o, f, and kr.

atomic radius of bromine (br) is 114 pm.

atomic radius of oxygen (o) is 73 pm.

atomic radius of fluorine (f) is 72 pm.

atomic radius of krypron (kr) is 112 pm.

the atomic radius of a chemical element is a measure of the size of its atom.

the atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.

the atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.