Due June 2, 2022 1. Turbidity is a measure of the cloudiness of water and can be used to indicate water quality. Higher turbidity usually indicates higher levels of disease-causing microbes, and has units of measure of formazin suspension units (FAUS). The following data was collected on the Rio Grande River during the late spring and early summer in order to observe any possible correlation between temperature and turbidity. Set a = 0.05. Temperature (°C) 22.9 24 22.9 23 20.5 26.2 25.8 Turbidity (FAU) 118 103 105 26 90 99 26.9 22.8 27 26.1 26.2 26.6 105 55 267 286 235 265 125 26.1 Temperature (°C) Turbidity (FAU) 100 (a) Find 30 and 3₁ for a linear model of turbidity as a function of temperature. (b) Find the regression, error, and total sums of squares. (c) Calculate R² and comment on its value. (d) Conduct t tests to see whether either of the model parameters are zero. (e) Give the two-sided confidence intervals for both model parameters. (f) Complete the ANOVA table and test for significance of the entire model. How does this compare to the answers of parts (d) and (e)? (g) Perform model adequacy checks. Are there any nonlinearities or unaccounted for vari- ables? (h) Plot the sample data, model, and 95% confidence and prediction intervals, all on the same figure.
