A four-sided tetrahedron was tossed 20 times. The outcomes of the hidden number were recorded.

\(\begin{array} {|c|c|} \hline
hidden \ number &frequencies \\ \hline
1 &4 \\ \hline
2 &6 \\ \hline
3 &5 \\ \hline
4 &5 \\ \hline
\end {array} \)

Find the experimental probability of a “Three” or “Four”.

A box contains 1 black and 8 white balls. Find the probability of getting two same colours if replacement does not occur. Answer to two decimal places.

Given  \(P\left( A \right) = \dfrac{1}{2}\) and \(P\left( B \right) = \dfrac{1}{3}\),   find  \(P\left( {A\text{ or }B} \right)\),   correcting to one decimal place.

\(\begin{array} {|c|c|c|c|} \hline
&iPhone &Samsung &no \ phone \\ \hline
Year \ 7 &26 &21 &9 \\ \hline
Year \ 8 &38 &22 &4 \\ \hline
Year \ 9 &42 &35 &3 \\ \hline
\end {array} \)

Find the probability that a randomly chosen student uses iPhone. Answer in decimal form.

The Venn diagram below shows the number of students in group \(A\), \(B\) or \(C\).   Find the number of students who not in both group \(A\) or \(B\).

A score was added to the set of scores: \( 13, 18, 20, 20, 22 \) and \( 26 \). The new mean is equal to \( 19\). What score was added?

Which measure would you use if you were looking to buy a house?

Find the median of the scores.

\( \begin{array}{|c|c|} \hline
Score & Frequency \\ \hline
5 & 6 \\ \hline
6 & 7 \\ \hline
7 & 12 \\ \hline
8 & 4 \\ \hline
\end{array} \)

Predict \(y\) when \(x = 8\)

Describe the strength of the linear relationship with correlation coefficient \(r = – 0.9\).