Types of variables

VariablesCan assume only one

value

ConstantsMeasurable factor that can

take any value while under observation/study

Types of variablesBased on cause and effect

1. Independent/ manipulated (IV)– “cause”

2. Dependent/ responding (DV)– “effect”/”observed”

3. Extraneous/ constant (EV)– other variables kept

constant

Types of variablesBased on the value of the variable

1. Continuous– with fractional

/decimal values

2. Discontinuous/ discrete– whole number

values, no fractions

Types of variablesBased on the scale of measurements

1. Nominal– qualitative description,

name

2. Ordinal/ranking– order or sequence– mutually-exclusive

classes

3. Interval– arbitrary zero point

4. Ratio– true zero point

Pineapple (Ananas comosus) contains bromelain extract, an aqueous protease enzyme that has been found to have anti-metastatic activity, low toxicology and have no side effects. Crude extracts were obtained from from a 1:1 ratio of distilled deionized water and filtered pineapple juice precipitated with saturated ammonium sulfate. Varying concentrations at 0%, 1%, 10%, and 100% of distilled deionized water and the extract were used to treat live acute lymphoblastic leukemia (ALL) cells cultured in fetal bovine serum for 24 hours. The cytotoxic efficiencies were obtained as indicated by the permeation of blue trypan dye of cell membranes of unviable cells. The 1% extract yielded a higher number of dead cells than total number of cells than the culture media. The 10% extract showed signs of contamination, and the 100% showed cell eruptions and bloated cells.