diff --git a/01_probability/source/1_probability.tex b/01_probability/source/1_probability.tex
index 1055834..20930d3 100644
--- a/01_probability/source/1_probability.tex
+++ b/01_probability/source/1_probability.tex
@@ -36,7 +36,7 @@ \section*{Introduction}
 that need to be tested and statistics is needed to interpret the
 results of user testing.
 
-Imaging a gambler wants to decide if a coin is fair; imagine they toss
+Imagine a gambler wants to decide if a coin is fair; imagine they toss
 it five times and get a head each time. Can they decide that the coin is
 fair. It is clear that they can't say that it is
 impossible that a fair coin would turn up heads five times; it is just
@@ -54,14 +54,14 @@ \section*{Introduction}
 \end{equation}
 the coin would produce such an unlikely result. Does this means the
 gambler can only be $94\%$ certain the coin is unfair? The idea of
-this unit it to learn how to calculate probabilities, the probability
+this unit is to learn how to calculate probabilities, the probability
 of five heads is an easy example of this, and how to make inferences,
 such as deciding the chance the coin is unfair.
 
 %% change to 1 9 90 900 etc
 It is very easy to confuse yourself with probability; here is a
-confusing problem. An evil genius has decided to tattoo their names on
-some peoples foreheads and in the usual over-elaborate evil genius
+confusing problem. An evil genius has decided to tattoo their name on
+some people's foreheads and in the usual over-elaborate evil genius
 manner they do it according to a diabolic game. A person is selected
 and forced into the tattoo parlour, the evil genius rolls two
 dice\footnote{Traditionally die is the singular of
@@ -89,7 +89,7 @@ \section*{Introduction}
 
 \section*{Probability}
 
-To start with we need to terminology and notation and this begins with
+To start with we need terminology and notation and this begins with
 a \textbf{sample space} $X$, this is the set of points; the idea is
 that these points are the possible outcomes of an experiment, or, it
 is said, the outcome of a \textbf{trial}. Initially it is useful to
diff --git a/01_probability/source/example_question.tex b/01_probability/source/example_question.tex
index f188030..36a49ed 100644
--- a/01_probability/source/example_question.tex
+++ b/01_probability/source/example_question.tex
@@ -14,7 +14,7 @@ \subsection*{1 Probability theory - example question}
 \begin{eqnarray}
   X&=&\{(4,1,1),(3,2,1),(3,1,2),(2,3,1),(2,1,3),\cr &&(2,2,2),(1,4,1),(1,1,4),(1,3,2),(1,2,3)\}
 \end{eqnarray}
-The event that the daughter gets at least three coints is
+The event that the daughter gets at least three coins is
 \begin{equation}
   E=\{(4,1,1),(3,2,1),(3,1,2)\}
 \end{equation}