Name: __________________________ Date: _____________________
Section______ TA: Lisha Roubert
Lab #1: Microsoft Excel Basics and Interpretation of Statistics
Objective: The objective of this exercise is to introduce you to the basics of Excel and interpretation of statistical results. You will also learn to interpret the results you obtain in a climate context. Remember to print out your plots and hand them in along with this sheet at the beginning of the next discussion session.
1) Using statistics to make comparisons - Go to the course website www.aos.wisc.edu/~roubert/aos_101_home.html and download the Lab1_Dataset1 I have uploaded for you. The dataset consists of the daily precipitation (inches) observations at Ithaca and Canandaigua, New York, for January 1987. Do the following with the downloaded data: a) Plot precipitation vs. date for Ithaca and Canandaigua (Both on the same plot). Remember to label your plots appropriately and write a title. b) Does the data for both locations show a similar trend (this means: do the plots have a similar shape even though there may be some variations)? What differences can you see between both plots? c) Can you identify a pattern in the data? Yes or No? Explain. (Hint: when there’s a pattern in the data you can easily predict what is going to happen in the future). To answer this question look to see if it continuously increases with time, if it continuously decreases with time, if it continuously oscillates, etc.) d) Calculate the total precipitation amount for January of 1987 in each location. In which location did it rain more?
2) Histograms -A Histogram is a graphical display of frequencies. It indicates how often an event ocurrs. In this problem the temperature is the event and we are interested in determining how often each temperature value ocurrs (frequency). Make a Histogram in Excel using the temperature data given in Table 1 and answer the questions below using the Histogram.
Table 1. June climate data for Guayaquil, Ecuador, 1951-1970. Asterisks indicate El Nino years.
Year
1951*
Temperature (◦C)
26.1

1952
1953*
1954
1955
1956
1957*
1958
1959
1960
1961
1962
1963
1964
1965*
1966
1967
1968
1969*
1970
24.5
24.8
24.5
24.1
24.3
26.4
24.9
23.7
23.5
24.0
24.1
23.7
24.3
26.6
24.6
24.8
24.4
26.8
25.2 a) Write the temperature values and their corresponding frequencies as shown in the Histogram. b) What temperature value occurred more often (has the highest frequency)? Which temperature value occurred less often (has the lowest frequency)? c) If you had a dataset that consists of snowfall days in Madison in December for the years
1996-2006. How could you represent the number of days of snowfall on a Histogram (how would you plot it in the Histogram)? (Think about it using the information you’ve learned about Histograms in this lab). d) Make the Histogram from part c) using this data.
Year
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
Days of Snowfall in Madison in December
15
10
19
20
10
17
10
17
19
13
10

3) Interpretation of results in a climate context -Using the same data in Table 1 plot temperature vs, year and answer the questions below. a) What years correspond to the 4 biggest peaks in the plot?
1.
2.
3.
4. b) Are these 4 years that correspond to the biggest peaks in the plot El Nino years? Based on the plot, do you think that El Nino has an effect on the temperatures of Ecuador? Why or why not
(use the plot to answer)? c) The map below shows a schematic view of the typical influence of El Niño on seasonal temperature and precipitation. Locate Ecuador on the map (Hint: It is near the equator as its name suggests). According to this map, what effect does El Nino have on the temperatures of
Ecuador? Does this agree with the results we found in the plot of temperatures vs. year for
Ecuador (Explain using both the plot and the map)?