| Exam Board | Edexcel |
|---|---|
| Module | S1 (Statistics 1) |
| Year | 2001 |
| Session | June |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Measures of Location and Spread |
| Type | Adding data values |
| Difficulty | Easy -1.2 This is a straightforward S1 question requiring direct application of standard formulas for mean and standard deviation from summary statistics, followed by a conceptual explanation about the effect of adding data values. Part (a) involves simple substitution into memorized formulas (μ = Σx/n, σ = √(Σx²/n - μ²)), and part (b) requires only basic understanding that adding values affects the mean. No problem-solving or novel insight needed—purely routine calculation and recall. |
| Spec | 2.02f Measures of average and spread2.02g Calculate mean and standard deviation |
\begin{enumerate}
\item Each of the 25 students on a computer course recorded the number of minutes $x$, to the nearest minute, spent surfing the internet during a given day. The results are summarised below.
\end{enumerate}
$$\Sigma x = 1075 , \Sigma x ^ { 2 } = 44625 .$$
(a) Find $\mu$ and $\sigma$ for these data.
Two other students surfed the internet on the same day for 35 and 51 minutes respectively.\\
(b) Without further calculation, explain the effect on the mean of including these two students.\\
(2)\\
\hfill \mbox{\textit{Edexcel S1 2001 Q1 [5]}}