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When
Do Monarchs Normally Arrive in Monticello, Arkansas?
Calcluating the Range, Median and Mean Arrival Dates
Step
1) Organize the data
First
Spring Monarch in Monticello, Arkansas
Observations by Dr. Jim Edson
1997-2003
|
| Date
of 1st Sighting |
Order (1st, 2nd, etc) |
| 03/29/97
|
5th |
| 03/25/98 |
3rd |
| 03/28/99 |
4th |
| 03/24/00 |
2nd |
| 04/03/01 |
6th |
| 03/23/02 |
1st |
| 04/12/03 |
7th |
Step
2) Determine
the Median
Because
there are 7 years' data, the the 4th year (March 28th) has 3 dates earlier
and 3 dates later.
- The
median arrival date is March 28th.
Step
3)
Determine
the Range
- The
earliest date is March
23.
- The
latest date is April
12.
- The
range is 21
days.
Step
4)
Calculate the Mean
| Value
|
Calendar
Date |
Date
of First Sighting
in Monticello, AR |
Add
Values to calculate the mean |
| 1
|
03/23 |
03/23/02
|
1
|
| 2
|
03/24 |
03/24/00 |
2 |
| 3
|
03/25 |
03/25/98 |
3 |
| 4
|
03/26 |
|
|
| 5
|
03/27 |
|
|
| 6
|
03/28 |
03/28/99
|
6
|
| 7
|
03/29 |
|
|
| 8
|
03/30 |
|
|
| 9
|
03/31 |
|
|
| 10
|
04/01 |
|
|
| 11
|
04/02 |
|
|
| 12
|
04/03 |
04/03/01
|
12
|
| 13
|
04/04 |
|
|
| 14
|
04/05 |
|
|
| 15
|
04/06 |
|
|
| 16
|
04/07 |
|
|
| 17
|
04/08 |
|
|
| 18
|
04/09 |
|
|
| 19
|
04/10 |
|
|
| 20
|
04/11 |
|
|
| 21
|
04/12 |
04/12/01
|
21
|
| |
|
Total
|
52
|
52
divided by 7 years = 7, so March 29
Copyright 2004-2007 Journey
North. All Rights Reserved.
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