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	About the Data About stream temperatures and canopy:     Stream temperature is an important ecological variable for a variety of riverine organisms. Some salmon and trout, for example, are very sensitive to water temperature at certain life stages, particularly as fertilized eggs and fry. In the Pacific Northwest, salmonids require rather cold water during the developmental stage to maximize survivability. Water temperature affects the amount of dissolved oxygen and the microorganisms upon which the fry and fingerlings feed, among others.     Stream temperature is controlled by a large number of factors, including (but not limited to) the temperature of rainfall, the amount of runoff and/or groundwater originating from melting snow and ice, the elevation of the drainage basin above sea level, the time of year, the water depth, how fast the water is moving and the amount of direct sunlight on the stream. This latter variable is dictated by the density and completeness of the canopy over the stream. Recognizing the role of direct sunlight in warming streams, Washington State's new logging regulations require more extensive streamside buffers of vegetation.     The Center for Urban Water Resources Management (CUWRM) and the Center for Streamside Studies (CSS) at the University of Washington in Seattle collected a large amount of data about lowland and foothills streams in 1998 and 1999, including discharge, water temperature, vegetation, etc. The UW collects this data in just a few days, in order to provide a "snapshot" of the streams without the effects of season, weather, etc. We have extracted a subset of the 1999 data.     The table and histograms show stream temperatures under a closed canopy of vegetation and in open sky with no shielding vegetation. The student should recognize immediately that widely different size of the two samples (n = 178 and n = 67) might introduce problems in comparing the distribution of values. As can be seen from the histograms and the student's computations, the means for these two groups are different, with colder water in the shaded streams. However, the standard deviations of both distributions are fairly large compared to this difference in mean temperatures. Is this difference in mean temperatures significant?     The student should be asked if these data are sufficient to test the idea that canopy plays a significant role in keeping the stream cool. For example, what was the amount of shading upstream from the measurement? Reference: http://depts.washington.edu/cuwrm/research.htm
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	View the Data  Source: Center for Urban Water Resources Management (CUWRM) & the Center for Streamside Studies (CSS) at the University of Washington in Seattle.   H20 Temp (C) Canopy Thornton 22.8 Closed, full shade Longfellow 15.6 Closed, full shade Longfellow 16.1 Closed, full shade Des Moines 17.5 Closed, full shade Garrison 15.0 Closed, full shade Garrison 14.8 Closed, full shade Soos 20.5 Closed, full shade Soos trib 0095 16.0 Closed, full shade Soos 21.0 Closed, full shade Coal 15.5 Closed, full shade Sunset 15.5 Closed, full shade Richards 14.9 Closed, full shade Richards 15.1 Closed, full shade Richards 16.2 Closed, full shade Sunset 11.9 Closed, full shade Valley 17.0 Closed, full shade Bear 18.0 Closed, full shade Stave 15.0 Closed, full shade Forbes 17.0 Closed, full shade Juanita 17.0 Closed, full shade Juanita 17.5 Closed, full shade Newaukum 15.0 Closed, full shade Newaukum 13.0 Closed, full shade Newaukum 15.0 Closed, full shade Morey 24.0 Closed, full shade Morey 21.0 Closed, full shade Spanaway 24.0 Closed, full shade Morey 24.5 Closed, full shade Clover 20.0 Closed, full shade Clover 17.0 Closed, full shade Clover 20.0 Closed, full shade Swan 14.0 Closed, full shade Swan 14.5 Closed, full shade Swan 15.0 Closed, full shade Flett 15.0 Closed, full shade Flett 15.8 Closed, full shade Chambers 19.3 Closed, full shade Chambers 15.7 Closed, full shade Chambers 16.8 Closed, full shade Leach 13.0 Closed, full shade Puget 12.5 Closed, full shade Puget 12.5 Closed, full shade Puget 12.0 Closed, full shade Puget 12.0 Closed, full shade Wollochet 16.5 Closed, full shade Crescent 14.4 Closed, full shade Donkey 15.6 Closed, full shade Crescent 14.4 Closed, full shade Crescent 17.2 Closed, full shade Deer 17.0 Closed, full shade Deer 17.0 Closed, full shade Deer 27.0 Closed, full shade Wildwood 14.0 Closed, full shade Wildwood 17.0 Closed, full shade Deer 17.0 Closed, full shade Wildwood 15.0 Closed, full shade Deer 17.0 Closed, full shade Clarks 9.5 Closed, full shade W. Hylebos 15.0 Closed, full shade W. Hylebos 12.0 Closed, full shade Hylebos 14.0 Closed, full shade Little Soos 19.5 Closed, full shade Jenkins 17.0 Closed, full shade Jenkins trib 0088 13.5 Closed, full shade Covington 23.0 Closed, full shade Covington 16.0 Closed, full shade Covington 16.0 Closed full shade Covington trib 0084 21.5 Closed, full shade Murray 15.0 Closed, full shade Murray 14.8 Closed, full shade Murray 13.0 Closed, full shade Murray 16.0 Closed, full shade Quilceda 16.0 Closed, full shade Quilceda 15.0 Closed, full shade Thomas 14.0 Closed, full shade Pigeon #1 15.0 Closed, full shade Pigeon #2 13.6 Closed, full shade Howarth 16.1 Closed, full shade Inglewood 12.7 Closed, full shade North 16.5 Closed, full shade North 18.5 Closed, full shade North 17.0 Closed, full shade North 18.0 Closed, full shade North 17.0 Closed, full shade North 16.5 Closed, full shade Silver 18.3 Closed, full shade Tambark 18.9 Closed, full shade Silver 18.9 Closed, full shade Silver 22.2 Closed, full shade Little Bear 13.0 Closed, full shade Little Bear 14.5 Closed, full shade LIttle Bear 14.0 Closed, full shade Scriber 21.0 Closed, full shade Lyon 17.0 Closed, full shade McAleer 16.5 Closed, full shade Dubuque 18.0 Closed, full shade Woods 13.5 Closed, full shade Woods trib 14.0 Closed, full shade Bear trib 0134A 17.5 Closed, full shade Vaughn 16.9 Closed, full shade Rocky 20.0 Closed, full shade Rocky 14.5 Closed, full shade Chico 25.0 Closed, full shade Beaver 13.5 Closed, full shade Beaver 15.0 Closed, full shade Salmonberry 14.0 Closed, full shade Salmonberry 19.5 Closed, full shade Salmonberry 14.5 Closed, full shade Salmonberry 16.5 Closed, full shade Beaver 13.5 Closed, full shade Gorst 12.0 Closed, full shade Gorst 12.0 Closed, full shade Gorst 14.0 Closed, full shade Gorst 12.5 Closed, full shade Chico 15.0 Closed, full shade Chico 16.0 Closed, full shade Chico 18.0 Closed, full shade Purdy 14.9 Closed, full shade Olalla 13.0 Closed, full shade Olalla 14.0 Closed, full shade Olalla 14.0 Closed, full shade Olalla 14.0 Closed, full shade Olalla 14.0 Closed, full shade Barker 13.0 Closed, full shade Clear 14.0 Closed, full shade Clear 14.0 Closed, full shade Clear 14.0 Closed, full shade Clear 16.0 Closed, full shade Clear 13.3 Closed, full shade Clear 14.5 Closed, full shade Clear 15.0 Closed, full shade Clear 17.5 Closed, full shade Clear 14.0 Closed, full shade Fisher 15.0 Closed, full shade Fisher 16.0 Closed, full shade Judd 14.5 Closed, full shade Judd 14.5 Closed, full shade Judd 15.0 Closed, full shade Judd 14.5 Closed, full shade Shingle Mill 12.0 Closed, full shade Morgan 14.0 Closed, full shade Kapowsin trib 13.0 Closed, full shade Kapowsin 20.0 Closed, full shade Kapowsin 21.0 Closed, full shade Kapowsin 20.0 Closed, full shade Fennel 14.4 Closed, full shade Fennel trib 18.9 Closed, full shade Little Bear 13.0 Closed, full shade Big Anderson 10.5 Closed, full shade Big Beef 14.0 Closed, full shade Schmitz 14.2 Closed, full shade Schmitz 14.2 Closed, full shade Taylor 16.7 Closed, full shade Taylor 16.1 Closed, full shade Taylor 16.1 Closed, full shade Taylor 16.1 Closed, full shade Mill 15.5 Closed, full shade Rock 13.0 Closed, full shade Rock 13.0 Closed, full shade E. Issaquah 15.0 Closed, full shade Holder 17.0 Closed, full shade Evans 16.0 Closed, full shade Bear trib 0115 17.0 Closed, stream in full shade Bear trib 0115 16.5 Closed, stream in full shade Bear 18.0 Closed, stream in full shade Little Soos 19.0 Closed, full shade Jenkins trib 0089 15.0 Closed, full shade Covington 17.0 Closed, full shade Rock 18.5 Closed, full shade Covington 14.0 Closed, full shade Laughing Jacobs 16.0 Closed, full shade Cherry 17.8 Closed, full shade N. Fork Cherry 19.4 Closed, full shade Cherry 17.4 Closed, full shade Griffin 16.0 Closed, full shade Canyon 15.0 Closed, full shade Patterson 15.0 Closed, full shade Patterson trib 0383 15.0 Closed, full shade       mean temp 16.02   std dev 2.83     bin freq. 9.5 1 10.5 1 11.5 1 12.5 10 13.5 16 14.5 36 15.5 29 16.5 26 17.5 23 18.5 11 19.5 5 20.5 6 21.5 5 22.5 2 23.5 1 24.5 3 25.5 1 26.5 0 27.5 1 Stream Name H20 Temp (C) Canopy Thornton 17.8 Open, full sun Thornton 23.3 Open, full sun Longfellow 14.4 Open, full sun Longfellow 14.7 Open, full sun Miller 18.0 Open, full sun Miller 18.0 Open, full sun Des Moines 18.0 Open, full sun Mc Donald 18.0 Open, full sun Mc Donald 18.5 Open, full sun Springbrook 27.5 Open, full sun Coal 23.0 Open, full sun Coal 23.0 Open, full sun South Prairie 17.5 Open, full sun Newaukum 14.0 Open, full sun Newaukum 13.0 Open, full sun Spanaway 24.0 Open, full sun Clover 26.5 Open, full sun Clover 17.0 Open, full sun Chambers 15.0 Open, full sun Chambers 15.9 Open, full sun Puget 13.0 Open, full sun Artondale 16.0 Open, full sun Artondale 14.4 Open, full sun Artondale 15.6 Open, full sun McCormick 14.4 Open, full sun Deer 21.0 Open, full sun Deer 21.5 Open, full sun Clarks 13.0 Open, full sun Clarks 13.0 Open, full sun Hylebos 15.0 Open, full sun West Hylebos 16.0 Open, full sun W. Hylebos 17.0 Open, full sun Hylebos 17.0 Open, full sun Little Soos 20.0 Open, full sun Newaukum 16.5 Open, full sun Murray 14.0 Open, full sun Allen 15.0 Open, full sun North trib 22.0 Open, full sun Silver 20.0 Open, full sun Little Bear 22.5 Open, full sun LIttle Bear 23.0 Open, full sun Little Bear 16.0 Open, full sun LIttle Bear 16.0 Open, full sun Swamp 19.0 Open, full sun Swamp 18.5 Open, full sun Lyon 17.0 Open, full sun Lyon 18.0 Open, full sun Sister of Friar 15.0 Open, stream in full sun Lake Roesiger 24.5 Open, full sun Vaughn 15.6 Open, full sun Rocky 15.0 Open, full sun E Rocky (Muck) 18.0 Open, full sun Square 11.7 Open, full sun Kapowsin trib 13.0 Open, full sun Little Bear 13.0 Open, full sun Rock 11.5 Open, full sun Prairie 20.0 Open, full sun Prairie 20.8 Open, full sun Bear 18.0 full sun Bear 19.0 Open, full sun Soos 17.8 Open, full sun Lakota 0387 13.0 Open, full sun Covington 16.5 Open, full sun Pine Lake 15.5 Open, full sun Griffin trib 11.0 Open, full sun Harris 18.5 Open, stream in full sun Harris 22.0 Open, full sun       mean temp 17.48   st dev 3.70   bin freq. 9.5 0 10.5 0 11.5 3 12.5 0 13.5 7 14.5 6 15.5 9 16.5 6 17.5 7 18.5 10 19.5 2 20.5 4 21.5 2 22.5 3 23.5 4 24.5 2 25.5 0 26.5 1 27.5 1
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