Assignment 2 for ENVS 202 Summer 2012

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Questions:

Make sure you show all work/reasoning - that is select an answer and justify it.

  1. Based on the last 300 UO Duck football games, the average points scored by the opposition was 23 points with a dispersion of 7 points. Therefore, 2/3 of the time that you attend a duck football game you would expect the opposition to score between

    1. 23 and 30 points
    2. 16 and 23 points
    3. 16 and 30 points
    4. 23 and 37 points
    5. insufficient information to know

  2. Based on the Duck football game data, a 1 in 100 scoring event by the opposition would be

    1. more than 23 points
    2. more than 30 points
    3. more than 37 points
    4. more than 41 points
    5. more than 45 points

  3. 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. what level above this average flood level would correspond to a 1 in a 1000 year flood event?

    1. 9.0 feet
    2. 14.0 feet
    3. 19.0 feet
    4. 24.0 feet
    5. can't tell from the data given

    A survey of 25 gas stations in the Eugene Area showed an average price for unleaded gas of $4.25 per gallon with a dispersion of 10 cents. Important note: 10 cents = 0.1$ - don't mix up your units for this question
    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.

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

    1) 50% 2) 15% 3) 5% 4) 1% 5) .1 %

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

    1) 50% 2) 15% 3) 5% 4) 1% 5) .1 %

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

    1) Eugene 2) Portland 3) Seattle

  7. About how many gas stations would I have to go to in Eugene to find a price of $4.00 per gallon?

    1) 10 2) 25 3) 50 4) 100 5) 1000

  8. The difference in mean gas prices between Eugene and Portland is

    1) not significant 2) marginally sig. 3) sig. 4) highly sig

  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 and calculate the Z-statistic.

    Part B)

    The dispersion around around the 1972 GPA was 0.7 and the dispersion around the 2011 GPA was 0.6. Determine the percentage of students whose GPA was above 3.5 in 1972 compared to 2011.

    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