The maximum daily temperatures (in °C) recorded in a town over 30 consecutive days are as follows:
22, 25, 27, 29, 30, 31, 28, 26, 24, 23,
32, 34, 35, 33, 31, 29, 28, 27, 26, 25,
30, 32, 33, 34, 35, 36, 37, 33, 31, 28
(i) State the minimum and maximum temperatures from the data.
(ii) The data are to be grouped into classes of width 5 °C, with the first class starting at the nearest multiple of 10 that is less than or equal to the minimum value. Write down the first three class intervals.
(iii) Construct a grouped frequency distribution table for the entire data set, including an additional cumulative-frequency column.
(iv) Using your table, determine the number of days on which the maximum temperature was at least 30 °C.