How many orders were studied ?
4 .
Ecommerce . com , a large Internet retailer , is studying the lead time ( elapsed time between when an order is placed and when it is filled ) for a sample of recent orders . The lead times are reported in days .
Lead Time ( days )
Frequency
0 up to 5 6
5 up to 10 7
10 up to 15 12
15 up to 20 8
20 up to 25 7
Total 40
What is the midpoint of the first class ?
5 .