please help this probability and statistics questions with clear steps and details, thank you so much(Q =2, Q can b used 2)

(a) The waiting time (in mins) of 18 randomly selected customers at ABC Sushi restaurant were recorded in the table below. 20 27 31 36 37 38 45 46 50 58 59 60 67 68 72 74 75 77 + (5 x Q) Suppose a grouped frequency distribution with 8 classes is to be constructed. Use the smallest data value as the lower limit of the first class. (i) Calculate the class width. (1 mark) (ii) Find the lower class limit of the 4th class. (1 mark) (iii) Find the number of data value(s) in the 2nd class. (1 mark) (iv) Find the upper class boundary of the 5th class. (1 mark) (b) Hong Kong people shop online more often than before the pandemic. The following grouped frequency distribution summarizes the number of items purchased by a random sample of 50 customers during Year 2021. Lower Class Limit Upper Class Limit Frequency 23 + Q 32 + Q 3 + Q 33 + Q 42 + Q 18 - Q 43 + Q 52 + Q 4 + Q 53 + Q 62 + Q 12 - Q 63 + Q 72 + Q 13 Use the information in the above grouped frequency distribution to construct a histogram. (4 marks) (c) Dining expenses of a sample of 300 customers 300 270 240 210 180 Cumulative frequency 150 120 90 30 0 61.5 82.5 103.5 124.5 145.5 166.5 187.5 Dining expense (in HK$) (i) Use the above ogive to find the midpoint of the 3d class. (1 mark) (ii) Based on the above ogive, 30% of the customers in the sample spent more than what amount of dining expenses (in $)? (1 mark)