• TABLE OF CONTENTS
HIDE
 Copyright
 Title Page
 Acknowledgement
 Table of Contents
 List of Tables
 List of Figures
 Purpose and method of study
 Celery
 Sweet corn
 Green peppers
 Irish potatoes
 Tomatoes
 Summary






Group Title: Economics mimeo report - Department of Agricultural Economics, University of Florida - EC 69-13
Title: Changes in seasonal FOB price patterns in Florida
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00071988/00001
 Material Information
Title: Changes in seasonal FOB price patterns in Florida celery, sweet corn, green peppers, Irish potatoes, and tomatoes, 1950-51 through 1965-66
Series Title: Economics mimeo report
Physical Description: iv, 21 leaves : ill. ; 28 cm.
Language: English
Creator: Parker, Arthur F ( Arthur Findlay ), 1943-
McPherson, W. W ( Woodrow Wilson )
University of Florida -- Agricultural Economics Dept
University of Florida -- Institute of Food and Agricultural Sciences
Publisher: University of Florida, Dept. of Agricultural Economics, Florida Agricultural Experiment Stations, Institute of Food and Agricultural Sciences
Place of Publication: Gainesville Fla
Publication Date: 1969
 Subjects
Subject: Celery -- Prices -- Florida   ( lcsh )
Corn -- Prices -- Florida   ( lcsh )
Peppers -- Prices -- Florida   ( lcsh )
Potatoes -- Prices -- Florida   ( lcsh )
Tomatoes -- Prices -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
statistics   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by Arthur F. Parker, Jr., and W.W. McPherson.
General Note: Cover title.
Funding: Agricultural economics mimeo report ;
 Record Information
Bibliographic ID: UF00071988
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 50806650

Table of Contents
    Copyright
        Copyright
    Title Page
        Title Page
    Acknowledgement
        Page i
    Table of Contents
        Page ii
    List of Tables
        Page iii
    List of Figures
        Page iii
        Page iv
    Purpose and method of study
        Page 1
        Page 2
        Page 3
    Celery
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
    Sweet corn
        Page 9
        Page 10
        Page 11
    Green peppers
        Page 12
        Page 13
        Page 14
    Irish potatoes
        Page 15
        Page 16
        Page 17
    Tomatoes
        Page 18
        Page 19
        Page 20
    Summary
        Page 21
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida





0
^ June 1969

a.. j ?


Economics Mimeo Report EC 69-13


CHANGES IN SEASONAL FOB PRICE


PATTERNS IN FLORIDA: CELERY, SWEET CORN


GREEN PEPPERS, IRISH POTATOES, AND TOMATOES


1950-51 through 1965-66








-By-
Arthur F. Parker, Jr., and W. W. McPherson










Department of Agricultural Economics
Florida Agricultural Experiment Stations
Institute of Food and Agricultural Sciences
University of Florida
N













ACKNOWLEDGEMENTS


Appreciation is expressed to Dr. Bobby R. Eddleman for his

valuable advice throughout this study, including preparation of the

manuscript.

Computing work was done at the University of Florida Computing

Center. Dr. Donald L. Brooke provided valuable assistance in obtain-

ing and classifying the data used in the study.
















TABLE OF CONTENTS


Acknowledgements

List of Tables .

List of Figures .

Purpose and Method

Celery . .

Sweet Corn .

Green Peppers. .

Irish Potatoes .

Tomatoes . .

Summary. . .








of Study.






o

. .


* .
. .


III.

IV.

V.

VI.

VII.


Page

i

iii

iii

1

4

9

12

15

18

21















LIST OF TABLES

Number Page

1. Celery for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 . . . . 7

2. Sweet corn for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 . . . . 11

3. Green peppers for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 . . . .... .14

4. Irish potatoes for fresh use: Mean monthly
indexes of FOB prices, Florida,1950-51
to 1965-66 ... . . . .. 17

5. Tomatoes for fresh use: Mean monthly
indexes of FOB prices, Florida, 1950-51
to 1965-66. . . . . .. 20


LIST OF FIGURES

Number Page

1. Celery for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 . . .. . 6

2. Celery for fresh use: Observed and estimated
monthly indexes of FOB prices, Florida, for
November and March, 1950-51 through 1965-66 8

3. Sweet corn for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 ... . . . 10

4. Green peppers for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 . . . . 13


iii















LIST OF TABLES

Number Page

1. Celery for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 . . . . 7

2. Sweet corn for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 . . . . 11

3. Green peppers for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 . . . .... .14

4. Irish potatoes for fresh use: Mean monthly
indexes of FOB prices, Florida,1950-51
to 1965-66 ... . . . .. 17

5. Tomatoes for fresh use: Mean monthly
indexes of FOB prices, Florida, 1950-51
to 1965-66. . . . . .. 20


LIST OF FIGURES

Number Page

1. Celery for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 . . .. . 6

2. Celery for fresh use: Observed and estimated
monthly indexes of FOB prices, Florida, for
November and March, 1950-51 through 1965-66 8

3. Sweet corn for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 ... . . . 10

4. Green peppers for fresh use: Estimated monthly
indexes of FOB prices, Florida, 1950-51
and 1965-66 . . . . 13


iii









Page 2 cont.


Number Page

5. Irish potatoes for fresh use: Mean monthly
indexes of FOB prices, Florida, 1950-51
to 1965-66 ................... 16

6. Tomatoes for fresh use: Mean monthly
indexes of FOB prices, Florida, 1950-51
to 1965-66 ..... ............ 19


iiii














I. PURPOSE AND METHOD OF STUDY


The production of fresh vegetables in Florida varies with the

seasons of the year. Therefore, it is expected that prices received

by Florida growers would also show definite seasonal patterns. The

objectives of this study were to identify and measure these seasonal

price patterns, and the shifts over time, for five of the more impor-

tant commodities produced for fresh use: celery, sweet corn, green

peppers, Irish potatoes, and tomatoes. The purpose of this report

is to present a summary of the findings with respect to the seasonal

patterns of prices and the changes that occurred between 1950-51

and 1965-66. A knowledge of the expected seasonal price patterns

should be useful where planting and harvesting dates can be changed

in order to take advantage of the periods of higher prices.

Time series data on prices generally contain four components:

long-term or secular trend, a cyclical pattern, a seasonal pattern and

random variation. At the same time, the seasonal pattern may be chang-

ing over time. Average monthly FOB prices for each month of the mar-

keting season from 1949-50 through 1966-67 were used in the analysis.

However, in one step of the analysis, 3-year moving average of price

ratios in each month was used. Consequently, the results pertain to the

1950-51 through 1965-66 period. The marketing season was defined as

those months in which production was at least 0.5 per cent of the total










production of the commodity for the entire growing season. Data were

obtained from published and unpublished materials supplied by the U. S.

Department of Agriculture and the Florida Department of Agriculture./

The first step in the analysis was to eliminate the secular

trend and cyclical patterns from the data by finding the average

prices for each year and regressing these average annual prices against
2/
time.- When each monthly price was divided by its corresponding esti-

mated yearly average price, the data were adjusted for secular trend

and for cyclical effects, and the monthly data were expressed in the

form of ratios or percentages of the respective annual average price.

The next step was to eliminate random variation from these

ratios by means of a three-term moving average consisting of ratios for

successive years for each month. This resulted in the loss of ratios

for the first and last years. After calculating the moving averages,

the ratios were then multiplied by a correction factor to give the

adjusted monthly indexes. The correction factor, obtained by dividing

the average ratio for each year into 100, adjusted the ratios so that



1/
U. S. Department of Agriculture, Agricultural Marketing Service,
Florida Vegetable Crops: Annual Statistical Summary, Orlando, Florida,
1958, 1959, and 1960 issues; U. S. Department of Agriculture, Statistical
Reporting Service, Florida Agricultural Statistics: Vegetable Summary,
Orlando, Florida, 1962, 1963, 1964, 1966, and 1967 issues; U. S. Depart-
ment of Agriculture, Agricultural Marketing Service, Potato Prices,
1909-52: Revised Estimates, Washington, D. C., Statistical Bulletin
Number 140, March 1954; U. S. Department of Agriculture, Statistical
Reporting Service, unpublished data, Orlando, Florida; and U. S. Depart-
ment of Agriculture, Statistical Reporting Service, Fresh Market Veget-
able Prices, Washington, D. C., Statistical Bulletin Number 318, June 1962.

2/
Details of statistical procedures and data used in the calcula-
tions are given in: Arthur Findlay Parker, Jr., "Seasonal Price Patterns
for Major Florida Agricultural Commodities," unpublished Master's Thesis,
Department of Agricultural Economics, University of Florida, Gainesville,
December, 1968.










the mean ratio for each year was equal to 100. Thus each monthly index

represents the price in the respective month expressed as a per cent of

the average annual price.

Finally the monthly indexes were regressed on time and tested for

statistical significance in order to measure the rates of change over

time in the monthly price patterns.

In presenting the results in the following sections, only the

estimates of the seasonal price patterns for the first and the last year

of the total period are shown in those cases where statistical tests

indicate that the patterns have changed over time. As exceptions to

this procedure, the actual and the estimated indexes for November and

March are presented for the entire period of years in the case of Celery.

These two examples illustrate the way in which the monthly indexes

have shifted over the 1950-51 through 1965-66 period. For those

commodities where the seasonal patterns have not changed over time, the

estimated mean seasonal patterns for the entire period are shown.















II. CELERY


Celery produced in Florida for fresh use is usually harvested

and sold during the months of November through June. In the beginning

of the 1950-51 to 1965-66 period the November prices were about 40 per

cent above the average seasonal price. There was a decline in each

following month until a low point was reached in March. Thereafter,

the prices rose until June when a price level about 22 per cent above

the seasonal average was reached (Fig. 1 and Table 1).

From 1950-51 to 1965-66, the monthly price pattern shifted

significantly. The estimated November price dropped from 145 to 86

per cent of the seasonal average, and the low price level was reached

in December, three months earlier than the low price at the beginning

of the period. At the end of the period, the price index increased in

each succeeding month, following the low point in December, up to the

highest peak in March when an index of 125 was reached. A sharp decline

occurred in April, and thereafter increases occurred in May and June

with the index standing at 11 per cent above the seasonal average at

the close of the season. Thus the notable shifts in the monthly price

pattern for celery were that the months of highest prices, or near

highest prices, November and December at the beginning of the period,

became the months of lowest prices at the end of the period. And the

month of lowest price, March, at the beginning of the period was the

month of highest prices at the end of the period.






5


As shown by the annual rates of change, or regression coefficients,

in Table 1, the November index decreased at the rate of 3.90 points

annually while the March index increased at the rate of 3.85 points

annually. Figure 2 shows the estimated and observed indexes for November

and March over the entire period.














Price
Index

150


140 -


130


120


110


100 -


90 -


80 -


70


60 -


Dec. Jan. Feb. Mar. Apr.


Month


Figure 1. --


Celery for fresh use: Estimated monthly indexes of FOB prices,
Florida, 1950-51 and 1965-66.


* Changes over time in these months were significant at the .05 level of
probability.


K,


1950 _l-r

-
V\


Nov.


-9


May


June













Table 1. Celery for fresh use: Estimated monthly indexes of FOB
prices, Florida, 1950-51 and 1965-66.





Month Estimated Index Rate of
1950-51 1965-66 annual change,
index points
index points-


November


December


January


February


March


April


June


Season average


122

100


86 ---------


*
72 ---------


93 ---------


111 ---------


125


98 ---------


104 ---------


111 ---------

100


-3.90
(0.75)

-2.34
(0.50)

0.22
(0.30)

1.50
(0.50)

3.85
(0.52)

1.01
(0.69)

0.37
(0.68)

-0.72
(0.70)


a/
-aThese numbers are the
the standard error in
coefficients.


linear regression coefficients with
parenthesis immediately below the


Changes over time in these months were significant at the
.05 level of probability.







NOVEMBER


Price
Index

160


140


120


100


80


60


Dcts indicate observed indexes
Line indicates estimated indexes


0


0 100


1961 1966


Figure 2. --


Celery for fresh use: Observed and estimated
November and March, 1950-51 through 1965-66.


monthly indexes of FOB prices, Florida, for


Price
Index


o a


1951


1956


1961


Year


1966


1951


1956


Year


_I __


MARCH













III. SWEET CORN


The season for sweet corn production in Florida begins in

October and runs through July. There was a very pronounced seasonal

price pattern. In the first of the period of years, prices in Octo-

ber tended to start around the seasonal average level and dropped in

November; thereafter, prices rose to a peak 31 per cent above the

seasonal average and then declined sharply.

The monthly price pattern shifted significantly during the

period included in this study (Fig. 3 and Table 2). The relative

prices in November, December and January fell while those in Feb-

ruary, March, April, and July increased although the increase in

March was not significant at the .05 level. The highest peak period

shifted from January to March. By the end of the period, prices at

the first of the season in October, November, December, and at the

end of the season in May, June, and July were below the seasonal

average price. During the mid-season of January through April,

prices were above the seasonal average. The high peak in prices was

reached one or two months later at the end of the period of years in

comparison with the beginning.

























s ,.
S'
S
S
f






Oct. Nov. Dec. Jan. Feb. Mar.


Apr. May June July


Month


Figure 3. --


Sweet corn for fresh use: Estimated
Florida, 1950-51 and 1965-66.


monthly indexes of FOB prices,


*Changes over time in these months were significant at the .05 level of
probability.


Price
Index


140


130


120


110


100


90


80


70


1950-


,




11






Table 2. Sweet corn for fresh use: Estimated monthly indexes of FOB
prices, Florida, 1950-51 and 1965-66.


Month


Estimated Index

1950-51 1965-66


October


November


December


January


February


March


April


May


June


July

Season average


107


98


119


131


114


116


84


78


79


76

100


98 ---------


81---------

82
*


114---------


130 --------


135 --------


117 --------

77--------


79--------


89--------

100


Rate of

annual change,
index points-


-0.60
(0.51)
-1.14
(0.46)

-2.48
(0.49)
-1.09
(0.48)

1.07
(0.41)
1.29
(1.00)
2.20
(0.56)
-0.05
(0.24)
-0.05
(0.33)
0.85
(0.27)


1 These numbers are the linear regression coefficients with
the standard error in parenthesis immediately below the
coefficient.

Changes over time in these months were significant at the
.05 level of probability.













IV. GREEN PEPPERS


The marketing season for green peppers in Florida starts in

October and extends through the following June. At the beginning of

the period under study, the estimated price index pattern began at

77 in October and increased sharply to a seasonal high of 144 in

November and December. Thereafter, there were declines in each

successive month to a low index of 69 in May.

Significant changes have occurred in the seasonal price pattern

for green peppers. The extremes in the monthly range have been reduced

from indexes of a low of 69 and a high of 144, a difference of 75

index points, to a low of 74 and a high of 124, a difference of 50

index points (Fig. 4 and Table 3).

The peak period has shifted from November and December, early

in the season, to the month of April. The monthly indexes in Novem-

ber, December, and January declined significantly during the years

included in this study. Significant increases occurred in April

and May. Thus the highest monthly prices have shifted from the early

to the later months in the marketing season.















Price
Index


145 ....
145 --------~


135 -


125 \
1950- 517

115 -


105 -
; \ 1965-66 7
i */
95 ,


85


75 .
'
65


0 I I I I I I I I

Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June

Month

Figure 4. -- Green peppers for fresh use: Estimated monthly indexes of
FOB prices, Florida, 1950-51 and 1965-66.


* Changes over time in these months were significant at the .05 level
of probability.





14






Table 3. Green peppers for fresh use: Estimated monthly indexes of
FOB prices, Florida, 1950-51 and 1965-66.





Month Estimated Index Rate of
1950-51 1965-66 annual change,

index points-


October


November


December


January


February


March


April


May


June

Season average


96


82


74


69


84

100


90---------


*
90 ---------


92---------

*
95 ---------


111 ---------


110 ---------

*
124 ---------


113 ---------


74 ---------

100


a These numbers are the linear regression coefficients with the
standard error in parenthesis immediately below the coeffi-
cient.

Changes over time in these months were significant at the
.05 level of probability.


0.92
(0.64)

-3.59
(1.34)

-3.46
(1.36)

-2.31
(0.67)

1.01
(1.26)

1.85
(0.89)

3.36
(0.41)

2.91
(0.54)

-0.68
(0.66)














V. IRISH POTATOES


Prices of Irish potatoes normally begin in December at a

seasonal high of 10 to 20 per cent above the seasonal average and

decline to a low point at the end of the season in June (Fig. 5 and

Table 4). There is a tendency for prices to be above or near the

seasonal average from December through April and to fall below the

seasonal average during the remaining months. Actually, the sea-

sonal price pattern falls into three periods: (1) December and

January, (2) February through March, and (3) May and June. Within

each of these periods, the differences among monthly prices are not

significant at the .05 level.

It is possible that there has been some reduction in the month-

to-month variation in prices, but generally the shifts in the monthly

indexes did not prove to be significant at the .05 level of probability.

However, on the average, extremes in price variations during the

harvest season may have been reduced. The difference in the range,

from a high of 122 to a low of 73, was 49 index points at the first of

the period and declined to 24 points at the end, when the high point

was 110 and the low was 86.

As shown by the coefficients of variation (Table 4) and the

67 per cent confidence interval, the monthly price index is more

stable February, March and May, than it is in the other months.





























670/o Confidence interval
-- I






\ /'
-- -






SS



S


'0
o >


Feb.


Mar. Apr.

Month


May


June


-- Irish potatoes for fresh use: Mean monthly indexes of FOB
prices, Florida, 1950-51 to 1965-66.


Price
In ex


130




120 -




110 -





100




90





80


Dec.


Jan.


Figure 5.



















Table 4. Irish potatoes for fresh use: Mean monthly indexes of
FOB prices, Florida, 1950-51 to 1965-66.




Month Mean Standard Coefficient
Index Deviation of
Variation


December 116 11.2 .10

January 114 12.7 .11

February 103 6.0 .06

March 99 8.2 .08

April 102 10.1 .10

May 86 6.0 .07

June 81 9.6 .12

Season average 100














VI. TOMATOES


Tomato prices begin the season in November at a level about

20 per cent above the seasonal average. Normally, there is a sharp

drop in December to about 10 per cent below the seasonal average.

Another peak is reached in March, and thereafter prices decline

during the remaining months until the end of the season in June

(Fig. 6 and Table 5). Thus, highest prices are normally received

in November and March and lowest prices occur in June, May and

December.

The seasonal pattern has not changed significantly over the

1950-51 to 1965-66 period. Year-to-year variations in monthly

prices were highest in December, February, March, and June as shown

by the coefficients of variation (Table 5) and the 67 per cent

confidence intervals around the mean indexes (Fig. 6).
















Price
Index


*
1
I


S.


670/o Confidence interval


-r I I I I I_


Nov. Dec.


Jan.


Feb.


Mar.


Apr.


June


Month


Figure 6. --


Tomatoes for fresh use: Mean monthly indexes
Florida, 1950-51 to 1965-66.


of FOB prices,


130




120


110




100




90





80




70

0



















Table 5. Tomatoes for fresh use: Mean of monthly indexes of
FOB prices, Florida, 1950-51 to .1965-66.




Month Mean Standard Coefficient
Index Deviation of
Variation



November 120 9.3 .08

December 91 9.8 .11

January 101 7.4 .07

February 103 10.0 .10

March 111 13.3 .12

April 102 7.1 .07

May 88 6.3 .07

June 84 11.3 .14

Season average 100













VII. SUMMARY


The objectives of this study were to identify and measure the

seasonal patterns, and shifts over time, in Florida FOB prices for

fresh celery, sweet corn, green peppers, Irish potatoes, and tomatoes.

The purpose of this report was to present the results that may be of

use to persons who have an interest in the markets of these commodities.

The monthly prices for 1949-50 through 1966-67 were used in

the analysis. Definite monthly patterns in prices were identified and

measured for each of the commodities listed above. Significant

changes in the monthly price patterns have occurred in the cases of

celery, sweet corn and green peppers. There appears to have been

little or no significant shifts in the seasonal price patterns for

Irish potatoes and tomatoes.

The annual rates of change (regression coefficients) in the

monthly patterns of celery, sweet corn, and green pepper should be

used with caution in any attempt to extend these shifts very far into

the future. It is quite possible that reactions in terms of changes

in seasonal supply patterns have changed or will change the directions

or rates of these shifts. Further research is planned on this matter

and on explaining these seasonal patterns in terms of variations in

supply and demand relationships.




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