The Common Fund is a firm that invests funds for colleges and universities. One of its investment vehicles is a short-term note that is supposed to compete with three-month Treasury bills.. The following table compares the monthly yields of the Common Fund short-tenn notesandthree-month Treasury bills (30). The average Common Fund yield was 5.22; the average Three-month T·bill increase, 4.51. ls that difference statistically significant? Let a = 0.05.
|
Month
|
Common Fund,.x
|
Three-month T-bill, y
|
|
July-91
|
6.71
|
5.75
|
|
Aug-91
|
6.19
|
5.51
|
|
Sep-91
|
6.23
|
5.38
|
|
Ocl-91
|
6JJ7
|
5.17
|
|
Nov-91
|
5.63
|
4.73
|
|
Dec-91
|
6.86
|
4.19
|
|
fan-92
|
3.93
|
3.93
|
|
Feb-92
|
3.95
|
3.95
|
|
Mar-92
|
4.16
|
4.16
|
|
Apr-92
|
4.26
|
3.8.3
|
|
May-92
|
4.26
|
3.15
|
|
Jun.-92
|
4.41
|
3.76
|