Cali Water Usage

California Water UsageResearch QuestionWhat factors influence California residences daily water usage?

HypothesesH0 (Null): The independent variables have no statistically significant associations with domestic daily water usage/person (gal.).HA (Alternative): The independent variables do have statistically significant associations with domestic daily water usage/person (gal.).

By Gabby Hernandez, Meme Torio, Kendall Thompson

1SourcesU.S. Geological SurveyCollected from local, state, and federal agenciesNational Oceanic & Atmospheric AdministrationCollected from Climatic Weather Stations2010 U.S. CensusCollected by the federal government (US Census Bureau)Sample SizeAll 58 California CountiesDependent Domestic Water Usage (Daily use/Person) gals. Independent Annual Precipitation (in.) Avg. Annual Temp. (F) Avg. Household Size % of Population w/ BA or higher (25+) % Black or African American % White (non-Hispanic or Latino) % Hispanic or Latino

About Our Data

VariableCoefficientsStandard ErrorP-ValueTotal Precipitation (In.)-0.6950.2460.007Mean Annual Temp. (F)1.2110.6150.055% Black or African American0.8541.3420.528% White (non-Hispanic or Latino)1.4470.5540.012% Hispanic or Latino-0.2390.550.666% of Pop. With BA or higher (25+)-0.750.3680.038Avg. Household Size

55.72421.8030.014F-stat6.287Significance F0.000Adjusted R-square0.394Number of Observations58

At the 95% confidence level the following variables were statistically significant:Total Annual Precipitation, % of CA residents who are White, % of Population w/ BA or Higher (25+), and Average Household Size.

Ex: As the percentage of the population (25 and older) with Bachelors degrees or higher increases by 1%, daily domestic water usage per person decreases by 0.75 gallons.

*The following variables were also included in the data, but were omitted from our regression because they were statistically insignificant:Agricultural Income, Land Area (sq. mi), Population Density (tot. pop/sq. mil), Median Household Income, and Private Nonfarm Employment.

Results:A multiple regression analysis was conducted to examine 7 potential predictors relationship with California residents daily water usage/person (gal.). The multiple regression model with all 7 predictors produced an adjusted R2 = 0.394 (meaning 39.4% of the dependent variable, Californias residents daily water usage/person (gal.), is responding to the independent variables).F(7, 58) = 6.287 > F-crit.: indicates all coefficients of the independent variables are not statistically equal to zero.P = 0.000 < 0.005: rejects the H0: stating that at the 95% confidence level, there is a significant relationship between the independent variable and California residents daily water usage/person (.gal) (4 out of 7 were statistically significant).Looking at the p-values < 0.05 for each predictor we can state:California residents daily water usage/person (gal.) has a moderately statistically significant direct association with percentage of Californians that are white AND average household size. California residents daily water usage/person (gal.) has a moderately statistically significant inverse association with total precipitation AND percentage of CA population with a B.A. or higher (25+)Possible improvements:Expand sample size to every CA city. Examine data from multiple years. This study only considers data collected from 2010.