Question 1 - A-Level Maths

Exam Board	Edexcel
Module	S1 (Statistics 1)
Year	2006
Session	January
Topic	Measures of Location and Spread
Type	Find median and quartiles from stem-and-leaf diagram

Over a period of time, the number of people $x$ leaving a hotel each morning was recorded. These data are summarised in the stem and leaf diagram below.

For these data,

write down the mode,
find the values of the three quartiles. Given that $\Sigma x = 1335$ and $\Sigma x ^ { 2 } = 71801$, find
the mean and the standard deviation of these data. One measure of skewness is found using $$\frac { \text { mean - mode } } { \text { standard deviation } } \text {. }$$
Evaluate this measure to show that these data are negatively skewed.
Give two other reasons why these data are negatively skewed.