Download Historical Temperature Trends

Data Analysis Project
Historical Temperature Trends
In this project we will look at historical temperature records for several cities and use statistical
methods to determine whether the data shows any significant patterns or trends in
temperature over time.
The SPSS data file for the project, TempRecs.sav is posted on Piazza along with Excel version.
The file contains the Annual Average Temperature records for two cities: New York, USA and
Sydney, Australia. For each year, the Annual Average Temperature value is calculated by
averaging high temperature readings from every day of that year, observed in a specific location,
Central Park for New York and Observatory Hill for Sydney.
In the project data file, three variables are recorded for each data point: the year (“year"), the
Annual Average Temperature for NYC ( "NYCtemp") and the Annual Average Temperature for
Sydney (Sydtemp".) The data are sorted by year in ascending order. For your convenience,
Sydney temperatures have been converted to Fahrenheit.
Original data sources:
http://www.erh.noaa.gov/okx/climate/records/monthannualtemp.html (for NYC)
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=36&p_display_type=dataFile&p_startYear=&
p_c=&p_stn_num=066062
(for Sydney)
Exercise 1
a) Use SPSS to produce a scatter plot of the temperatures for New York City using the “year” as
x-axis.
b) Provide a paragraph describing whether you see any trends or patterns in the data from your
graph.
c) Produce a similar plot for Sydney.
d) In a paragraph, describe what you see for that city
e) Describe any similarities and/or differences you observe between Sydney and New York City.
Extra Credit:
Online, find the temperature records for the city of your choice, the records have to go
back at least 120 years. In one sentence, explain why you chose this specific city. Repeat
Exercise 1 for your city.
Exercise 2
a) Use SPSS to find summary measurements for the annual average temperatures in New York
City over the entire recorded period (1869-2013): min, max, mean, median and standard
deviation.
Identify the hottest year and the coldest year.
Data Analysis Project
b) Use SPSS to make a Box Plot of the data set.
c) Repeat this exercise for the historical temperature values in Sydney.
d) Write a paragraph describing how the two cities differ in temperature. Hint: Base you answer
on any notable differences you observe in the two Box Plots.
Extra Credit: Repeat exercise 2 for the city of your choice.
Exercise 3
a) Use SPSS to obtain a frequency distribution histogram of the annual average temperatures in
New York City. Describe the “shape” of distribution.
b) Repeat the process for Sydney, using the same class limits you had for New York City.
c) In a paragraph, describe any similarities and differences you observe between the shapes of
the two distributions and interpret the meaning of these differences.
Extra Credit: Repeat exercise 3 for the city of your choice.
Exercise 4A
Limit your attention to the most “recent” temperature data, (which we define as years 19902013), for New York City. Answer the following questions:
a) For how many years during the recent period, did the annual temperature rise above the
historical mean calculated for the entire period? Does this represent a reasonable, relatively
large or relatively small percentage of the recent years?
b) Of the 25 warmest years in recorded history, what percentage occurs during the recent
period? Do you think the recent period has more or less than its fair share of warmer years?
(Hint: It may help to re-sort the data according to temperature).
c) Is the mean temperature for the recent period higher or lower than that of the entire period?
Calculate the z-score for the recent mean based on the mean and standard deviation for the
entire period. What does the value of the z-score tell you about the difference between the
two means?
d) Draw a Box Plot for the recent years and place it next to the Box Plot obtained from the data
corresponding to the years prior to 1990. Are there any noteworthy differences between the
two?
e) Write a paragraph to summarize your findings: are NYC annual temperatures notably
different in recent times from what they were in the earlier part of the observation period. In
what way?
Data Analysis Project
Exercise 4B
Repeat the process for Sydney
Extra Credit: Repeat exercise 4 for the city of your choice.
Exercise 5A
a) Use a statistical package to find the value of the linear correlation coefficient between “year”
and “NYCtemp”
b) Is the correlation significant? Explain the reason for your answer
c) If the correlation is significant, what does it imply about the trend in temperatures?
d) Find the equation for the least squares regression (LSR) line
e) Interpret the meaning of the slope of the LSR line.
f) Based on the equation of LSR line, what is the “best predicted” value for the NYC Annual
Average Temperature for 2013? How accurate is the prediction?
g) Can we use this LSR line equation to predict the Annual Average Temperatures for the future?
Explain.
h) Write a paragraph to summarize your findings: Is there statistically significant evidence of
any pattern or trend in temperature over the observation period in NYC?
Exercise 5B Repeat the process for Sydney.
Extra Credit: Repeat exercise 5 for the city of your choice.
Exercise 6

Does your analysis of the historical temperature data for several cities, provide evidence for
the existence of the temperature increasing trend around the world? Why or why not?
Include one graph or chart to support your claim.

Can you conclude, based on your analyzes, whether the Global Warming is occurring? Why
or why not?