36
Chapter 1
Problem 1.10 The life experience of electric lamps
=
Select the best distribution for the data
Class
Renewals of original
Call no.
interval
units, or frequency
0
0-99.5
755
1
99.5-199.5
1,142
2
199.5-299.5
2,340
3
299.5-399.5
3,322
4
399.5M99.5
3,775
5
499.5-599.5
4,303
6
599.5-699.5
4,983
7
699.5-799.5
5,511
8
799.5-899.5
5,738
9
899.5-999.5
5,888
10
999.5-1,099.5
5,888
11
1,099.5-1,199.5
5,838
12
1,199.5-1,299.5
5,511
13
1,299.5-1,399.5
4,983
14
1,399.5-1,499.5
4,303
15
1,499.4-1,599.5
3,775
16
1,599.5-1,799.5
3,322
17
1,699.5-1,799.5
2,340
18
1,799.5-1,899.5
1,142
19
1,899.5-1,999.5
755
75,614
Taken from the mortality experience of electric lamps obtained
from periodic inspections of lamps by the National Electric
Lamp Association in 1915. The mortality is due entirely to
use and therefore does not represent any replacements due to
inadequacy, obsolescence or public requirements.