The stem-and-leaf diagram below represents data collected for the number of hits on an internet site on each day in March 2007. There is one missing value, denoted by \(x\).
Stem-and-leaf diagram:
| Stem | leaf | |
|---|---|---|
| 0 | 0 1 5 6 | (4) |
| 1 | 1 3 5 6 6 8 | (6) |
| 2 | 1 1 2 3 4 4 4 8 9 | (9) |
| 3 | 1 2 2 2 x 8 9 | (7) |
| 4 | 2 5 6 7 9 | (5) |
Key: \( 1 \mid 5 \) represents 15 hits.
(i) Find the median and lower quartile for the number of hits each day.
(ii) The interquartile range is 19. Find the value of \(x\).
The lengths of time in minutes to swim a certain distance by the members of a class of twelve 9-year-olds and by the members of a class of eight 16-year-olds are shown below.
9-year-olds: 13.0, 16.1, 16.0, 14.4, 15.9, 15.1, 14.2, 13.7, 16.7, 16.4, 15.0, 13.2
16-year-olds: 14.8, 13.0, 11.4, 11.7, 16.5, 13.7, 12.8, 12.9
(i) Draw a back-to-back stem-and-leaf diagram to represent the information above.
(ii) A new pupil joined the 16-year-old class and swam the distance. The mean time for the class of nine pupils was now 13.6 minutes. Find the new pupil’s time to swim the distance.
(i) The diagram represents the sales of Superclene toothpaste over the last few years. Give a reason why it is misleading.
(ii) The following data represent the daily ticket sales at a small theatre during three weeks.
52, 73, 34, 85, 62, 79, 89, 50, 45, 83, 84, 91, 85, 84, 87, 44, 86, 41, 35, 73, 86.
(a) Construct a stem-and-leaf diagram to illustrate the data.
(b) Use your diagram to find the median of the data.
The Lions and the Tigers are two basketball clubs. The heights, in cm, of the 11 players in each of their first team squads are given in the table.
| Lions | 178 | 186 | 181 | 187 | 179 | 190 | 189 | 190 | 180 | 169 | 196 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Tigers | 194 | 179 | 187 | 190 | 183 | 201 | 184 | 180 | 195 | 191 | 197 |
Lakeview and Riverside are two schools. The pupils at both schools took part in a competition to see how far they could throw a ball. The distances thrown, to the nearest metre, by 11 pupils from each school are shown in the following table.
| Lakeview | 10 | 14 | 19 | 22 | 26 | 27 | 28 | 30 | 32 | 33 | 41 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Riverside | 23 | 36 | 21 | 18 | 37 | 25 | 18 | 20 | 24 | 30 | 25 |