Answer:
(a) 2 ≤ t < 4
(b) Yes, the data supports the statement
Explanation:
(a) The median interval is given by the interval of the (n + 1)/2 th term
The number of customers that waited at the supermarket checkout, n = 80
Therefore, the median = (80 + 1)/2 th customer = 40.5 th customer = The41st customer
From the given table, the time interval of the 41 st customer = 2 ≤ t < 4
The class interval of the median = 2 ≤ t < 4
(b) The number of customers that wait less than 6 minutes is given as follows;
32 customers weight 0 ≤ t < 2 minutes
19 customers weight 2 ≤ t < 4 minutes
20 customers weight 4 ≤ t < 6 minutes
The total number of customers that wait less than 6 minutes = 32 + 19 + 20 = 71 customers
The percentage of customer that wait less than 6 minutes = 74/80 × 100 = 92.5% ≈ 90%
Therefore, the data supports the manager's statement that (approximately) 90% of the customers wait less than 6 minutes