Read through the article, Controls on methane concentrations and fluxes in streams draining human-dominated landscapes Crawford & Stanley, 2016), and answer the following questions.

a. What two attributes did the researchers use to stratify their random sample in the stream survey?

b. Which of the physical and chemical variables from the stream survey had the strongest correlation with partial pressure of CH4 (pCH4)?

c. Using the results of the laboratory sediment experiment reported in Table 2, a full conclusion for the main effect of Site on net sediment CH4 production, citing the appropriate statistics.

d. For the post-hoc analysis run on the model reported in Table 2, what type of correction did these researchers use? What significant differences did their post-hoc analysis indicate?

Biostats SDS 328M Homework 10 Part 1 - Hand work (all work and graphs must be done by hand). Write your answers onto one or more separate sheets of paper. Clearly mark each sheet with your name and your lab time. Round all answers to 3 decimal places and assume =0.05 unless otherwise noted. 1. As part of a study on the bluntnose minnow (Pimephales notatus) you want to determine which factors contribute to how many of these fish live in parts of a stream. So you sampled 80 different sections of a stream and counted the number of minnows per cubic meter, the water temperature (C), the water depth (meters), and whether or not there was a predator present (yeso). After confirming all relevant assumptions, you ran a general linear model predicting the density of bluntnose minnows: Intercept b -4.61 SE 0.45 Water Temp 0.51 0.37 Water Depth Predator (0=No, 1=Yes) 12.33 -8.71 5.13 1.56 a. Calculate the test statistics for each explanatory variable in the model. Which predictors explain a significant amount of variation in the response variable? (3pt) b. Write out the full regression equation for predicting the density of bluntnose minnows in this stream. (1pt) c. Interpret the estimate (slope) for Predator in context. (2pt) d. Predict the bluntnose minnow density in a part of the stream that is 12C, 2.5 meters deep, and has a predator present. (1pt) 2. Read through the article, Controls on methane concentrations and fluxes in streams draining human-dominated landscapes (Crawford & Stanley, 2016), and answer the following questions. a. What two attributes did the researchers use to stratify their random sample in the stream survey? (1pt) b. Which of the physical and chemical variables from the stream survey had the strongest correlation with partial pressure of CH4 (pCH4)? (1pt) Copyright 2017 Dept. of Statistics and Data Sciences, UT Austin c. Using the results of the laboratory sediment experiment reported in Table 2, write a full conclusion for the main effect of Site on net sediment CH4 production, citing the appropriate statistics. (2pt) d. For the post-hoc analysis run on the model reported in Table 2, what type of correction did these researchers use? What significant differences did their posthoc analysis indicate? (2pt) Part 2 - R work (must be done in R) Copy and paste your R code and output into a word document to submit to Canvas. Follow these instructions to import the necessary dataset: Before opening the dataset needed for this problem, you'll need to call the \"car\" package. Run the following line of code: > library(car) Now you can import the \"Salaries\" dataset and use it to answer the question below. Name the data frame with your UT EID: > my_eid