Refer to Exhibit 15-25. We want to test whether the parameter ₁ (that is, the coefficient on trade price) is significant. The test statistic equals

Suppose the observational units in a study are the patients arriving at an emergency room on a given day, 11 Nov 2019. For the following indicate whether it can legitimately be considered a variable or not: Whether or not men have to wait longer than women     yes       no

2. State whether the variables described have a positive correlation, a negative correlation, or no correlation. (a) Income and SAT scores (b) Length of a person's hair and how far they sit from the screen in a movie theater. (c) Hours of exercise per week and blood pressure.

8. Trace metals in drinking water affect the flavor of the water, and un-usually high concentration can pose a health hazard. Table 1 shows trace-metal concentrations (zinc, in mg/L) for both surface water and bottom water at six different river locations. Our aim is to see if surface water concentration (x) is predictive of bottom water concentration (y). a. State the independent and dependent variable? b. State the Ho y HA c. Draw a scatter diagram to show a possible association between the concentrations and check to see if a linear model is justified. d. Calculate the correlation coefficient and provide your interpretation. e. Find the regression equation and pro your interpretation. Table 1 1123456 Location Bottom 0.430 0.266 0.567 0.531 0.707 0.716 Surface 0.415 0.238 0.390 0.410 0.605 0.609 I