Assignment 2 for ENVS 202 Summer 2015

Homework Upload Link

Questions: Instructions:

    Another data graphing exercise:
      a) Go to this chart library and scroll down on the page until you see the "CODE IT YOURSELF on JSFIDDLE" button.

      Upon going to JSFIDDLE your screen should look like this:



      b) cut out the data in the edit code window that is highlighted by the blue lines:



      Now paste in the following data table in the exact place where you cut out the previous one. (if its not exact it won't work) 



           ['1855' ,-.112,0.000,0.060,0.172],
     ['1865' ,-.122,0.010,0.070,0.202],
     ['1875' ,-.040,0.160,0.220,0.420],
     ['1885' ,0.036,0.140,0.200,0.304],
     ['1895' ,-.186,-.040,0.020,0.166],
     ['1905' ,-.195,-.110,-.050,0.229],
     ['1915' ,-.183,-.100,-.040,0.230],
     ['1925' ,0.038,0.120,0.180,0.262],
     ['1935' ,0.322,0.440,0.500,0.618],
     ['1945' ,0.330,0.520,0.580,0.770],
     ['1955' ,0.184,0.390,0.450,0.656],
     ['1965' ,0.221,0.470,0.530,0.779],
     ['1975' ,0.472,0.760,0.820,1.108],
     ['1985' ,1.104,1.310,1.370,1.576],
     ['1995' ,1.485,1.600,1.660,1.775],
     ['2005' ,1.766,1.860,1.920,2.012],
     ['2015' ,2.282,2.430,2.450,2.541]


      After doing this, hit the Run button near the top to produce your new plot.

      Capture that graph and embed it in your assignment document.

    The chart you have made plots the average temperature of the land surface of the earth, as averaged over 10 year intervals, compared to the basleine 1850 temperature, in units of degrees C. Also plotted is the standard deviation of the temperature during these 10 year time windows. (The last plotted point is an extrapolation to next year). The length of the line going through each rectangular box represents +/- one units of standard deviation.

  1. From the plot you just constructed:

      a) Describe the behavior of the average temperature difference as a function of time.

      b) Describe the behavior of the standard deviation (the measure of volatility around the mean) as a function of time.


  2. The current (2015) population of Eugene is approximately 155,000 people. If the population growth rate remains at 4% per year, approximately when will the city of Eugene have 500,000 people? (show your work)

  3. The following is a list of total points in 12 randomly selected NFL football games 

    23
31
17
25
12
48
35
27
41
63
24
22
    Calculate the standard deviation of these scores any way you like (you can use the standard deviation fit to data tool in the resources section by just cutting and pasting the numbers into that tool)

    Your urban legend friend (some one that believes anecodal evidence much more than quantatitave reasoning) insists that scoring more than 45 points in an NFL game is highly improbable (meaning it happens less than 1% of the time).

      a) Based on this data, what would you tell your friend?

      b) Based on this data, what should be the level of the 1% event?

  4. The Columbia River near Pasco has had about 100 years worth of flood measurements made. Those data indicate a mean flood level of 9.0 feet with a dispersion of 5.0 feet around that mean flood level. Based on this data. how many feet above this average flood level would correspond to a 1 in a 1000 year flood event? (show your work)



    Important note: 10 cents = 0.1$ - don't mix up your units for these questions 5--8

    A survey of 25 gas stations in the Eugene Area showed an average price for unleaded gas of $4.25 per gallon with a standard deviation (dispersion) of 10 cents.

    A survey of 25 stations in the Portland area had an average of $4.35 per gallon with a dispersion of 10 cents.

    A survey of 50 stations in the Seattle area had an average of $4.30 per gallon with a dispersion of 21 cents.



    Show all work/reasoning for the questions below:


  5. What is the probability that in Eugene you will pay more than $4.45 per gallon?

  6. What is the probability that in Portland you will pay more than $4.45 per gallon?

  7. Which location has the highest probability of paying $4.50 or more per gallon.

  8. Use the Z-test as described in the lecture material to determine if the difference in mean gas prices between Eugene and Portland is statistically significant.



  9. The following data represent the average GPA of UO Students as a function of year.

    Part A)

    Use the Z-test as described in the lecture material and divide the data into two halves and calculate the Z-statistic.

    Part B)

    The dispersion around around the 1972 GPA was 0.7 and the dispersion around the 2013 GPA was 0.6. Determine the percentage of students whose GPA was above 3.5 in 1972 compared to 2013.

    Part C)

    Using these results (and not your personal opinion), argue whether or not grade inflation is significant at the UO.

    The Data: 

    1972	2.43
1973	2.44
1974	2.45
1975	2.44
1976	2.47
1977	2.48
1978	2.5
1979	2.52
1980	2.56
1981	2.58
1982	2.58
1983	2.58
1984	2.57
1985	2.6
1986	2.6
1987	2.59
1988	2.58
1989	2.6
1990	2.64
1991	2.66
1992	2.74
1993	2.76
1994	2.79
1995	2.78
1996	2.8
1997	2.82
1998	2.84
1999	2.79
2000	2.82
2001	2.85
2002	2.87
2003	2.89
2004	2.91
2005	2.9
2006	2.93
2007	2.94
2008    2.96
2009    2.97
2010    3.01
2011    3.03
2012    3.07
2013    3.13