Means And Standard Deviations Environmental Science Homework Help

You have been assigned by your company, “Progress ‘R Us” to study if there has been a decline in recent years of Adult Chinook salmon at the McNary Dam and if there is a mortality rate of this species between The Dalles Dam and the McNary Dam.
You have the following raw data to work with (from HERELinks to an external site.) — the data are actual fish counts at the Dam.
Using this data answer the questions that are posed below the data table.
These tools will be needed:
1. Download the Chart Tool 2. Use this tool to determine means and standard deviationsLinks to an external site.
3. Use the Z-test Calculator when needed
2014772107605907 2013757403582908 2012413376341652 2011440862388058 2010543241471747 2009350717232094 2008 331468 224684 2007 187015 129062 2006 312102 197539 2005 363993 249633 2004 511767 342302 2003 546394 368345 2002 540173 380976 2001 556690 437120 2000 253067 152763 1999 171079 106891 1998 133619 99432 1997 207552 145958 1996 154044 101616 1995 108980 84692 1994 136288 107889 1993 172655 133097 1992 141347 111723 1991 116181 82636 1990 174773 121159 1989 252848 151486 1988 308355 184870 1987 356113 237200 1986 266175 207819 1985 223400 161401 1984 132990 102675 1983 114855 91905 1982 112517 69246 1981 101257 63427 1980 93935 63215 1979 107737 69756 1978 167434 123542 1977 169886 128363 1976 126200 80900 1975 142900 83400 1974 137400 93300 1973 208900 148500 1972 187000 146700 1971 165100 134000 1970 175900 136000 1969 215300 173600 1968 198300 155400 1967 181400 146500 1966 204200 179700 1965 127400 101600 1964 153000 138600 1963 125800 110500 1962 169200 133800 1961 201300 131800 1960 196900 154300 1959 207500 171500 1958 301900 226100 1957 312700 292700
a) Enter the data into the chart tool (you can minimize typing by just entering the data in units of thousands so instead of entering 312700 just enter 312 or 313 if you want to round up). Include your chart in your homework submission and comment on the ensuing pattern of the data that you notice.
b) Compute the means and standard deviations over the entire data period (1957-2014) and use the Z-test to show that the Counts at McNary Dam are significantly lower than at the Dalles Dam.
c) For just the Dalles Dam counts: Compute the average and standard deviation of the counts between the period 2001- 2014 and from 1957-1999. Use the Z-test to determine if there is a significant difference between these two time periods.
d)From the result you just got above, what does this tell you about the relation between dams and decreasing salmon in the Columbia River system. Offer a data informed opinion and not your personal opinion.
e) Compared to the 2001-2014 period (again Dalles Dam) are the low counts observed in 2007 statistically significant? If so, what factors in that year do you think might have caused this (temporary) decline (do some research to support your statements)

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