| Exam Board | CAIE |
|---|---|
| Module | S1 (Statistics 1) |
| Year | 2010 |
| Session | November |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Measures of Location and Spread |
| Type | Find coded sums from raw data |
| Difficulty | Easy -1.2 This is a straightforward application of coding formulas for mean and variance. Part (i) requires simple algebraic manipulation of Σ(x-60) to find the mean. Parts (ii) and (iii) use standard results about how sums change under linear transformations. All steps are routine recall with minimal problem-solving, making this easier than average. |
| Spec | 2.02g Calculate mean and standard deviation |
4 Delip measured the speeds, $x \mathrm {~km}$ per hour, of 70 cars on a road where the speed limit is 60 km per hour. His results are summarised by $\Sigma ( x - 60 ) = 245$.\\
(i) Calculate the mean speed of these 70 cars.
His friend Sachim used values of $( x - 50 )$ to calculate the mean.\\
(ii) Find $\Sigma ( x - 50 )$.\\
(iii) The standard deviation of the speeds is 10.6 km per hour. Calculate $\Sigma ( x - 50 ) ^ { 2 }$.
\hfill \mbox{\textit{CAIE S1 2010 Q4 [6]}}