To test the difficulty level of a new computer game, a company measures the time taken for a group of players to complete the game. Their results are displayed in the table alongside.
Completion time (t min)
Number of players
0≤t<30
1
30≤t<60
4
60≤t<90
12
90≤t<120
18
120≤t<150
7
150≤t<180
2
(1) How many players were surveyed?
(2) Write down the modal class.
(3) Draw a cumulative frequency graph for the data.
(4) The game is considered too easy if either the mean or median completion time is below 90 minutes.
- i** Estimate the median completion time using your cumulative frequency graph.
- ii** Estimate the mean completion time.
- iii** Hence comment on whether the game is too easy.
(5) Complete this sentence:
The middle 50% of players completed the game in times between ..... and ..... minutes.