The marketing manager of a hotel wants to investigate the expenditure of customers during the recent staycation promotion. The total amounts of expenditure (corrected to the nearest dollars) of randomly selected customers are summarized as follows.

Expenditure ($) ; Frequency

Below 1,000 ; 6

1,000 - below 2,000 ; 14

2,000 - below 3,000 ; 17

3,000 - below 4,000 ; 27

4,000 - below 5,000 ; 31

5,000 - below 7,000 ; 5

(a) Calculate the mean, median and standard deviation of the expenditure.

(b) Calculate the coefficient of skewness using results in (a) and interpret your result briefly.

(c) Estimate, from the frequency distribution table, the proportion of customers who spend between $2,800 and $4,800 in the hotel.

(d) Estimate, from the frequency distribution table, the expenditure that exceeded by 40% of the customers in the hotel.