I have shamelessly stolen QM's new quiz format idea. Feel free to make similar quizzes (especially if you want to make an easier version). For each category, select the answer that does not belong.
Keep scrolling down for answers and more stats ...
1. Prime numbers
91 = 7 × 13
91
19
79
97
2. Triangle centres (a triangle centre is a point that can be defined as the "centre" of the triangle by some metric)
"Epicentre" is a term used in seismology, in connection to earthquakes. It has nothing to do with triangles.
Centroid
Circumcentre
Epicentre
Orthocentre
3. Distributions in statistics
Standard normal distribution
Conjunct distribution
Poisson distribution
Binomial distribution
4. "Fundamental" theorems
Fundamental theorem of algebra
Fundamental theorem of geometry
Fundamental theorem of calculus
Fundamental theorem of arithmetic
5. Real numbers
There are many mathematical formalisations of the concept of infinity, but it is certainly not a real number.
Googolplex
∞
π
0
6. Things that can be represented by a symbol commonly found on a QWERTY keyboard
A limit is usually denoted by "lim"
Greater than
Limit
Subtract
Factorial
7. Constants named after individuals
There is a category of numbers called Fermat numbers, but it doesn't refer to a specific constant.
Skewes's number
Fermat's number
Graham's number
Euler's number
8. Mathematicians who made significant contributions to number theory
As a mathematician, Newton is notable mostly for inventing calculus.
Isaac Newton
Leonhard Euler
Pierre de Fermat
Carl Friedrich Gauss
9. Regular (Platonic) three-dimensional shapes
It is impossible to construct a regular enneahedron (which would be a nine-faced shape)
Tetrahedron
Cube
Icosahedron
Enneahedron
10. Square numbers
Square numbers can never end with the digit 2.
4792
16384
1234321
0
11. Things there are known to be infinitely many of
It is not known whether there are infinitely many perfect numbers or not.
Rational numbers between 0.499 and 0.501
Digits in the full decimal expansion of π
Prime numbers
Perfect numbers
12. Theories in maths
Group theory
Girth theory
Graph theory
Galois theory
13. Mathematicians of the 20th century
Riemann died in 1866.
G.H. Hardy
Paul Erdős
Srinivasa Ramanujan
Bernhard Riemann
14. Mathematical terminology relating to vegetation
As of yet, there is no mathematical object commonly called a "bud". Trees are found in graph theory, fields are found in group theory and most people have heard of square roots.
Field
Tree
Bud
Root
15. Trigonometric functions
There is no such thing as a bicosine. The arctangent is the inverse function of the tangent and the cosecant of an angle is equal to one divided by the sine of the angle.