The critical values separate the rejection region from the non-rejection region. True False

Changing from a two-tail test to a one-tail test Increases the probability of a Type Il error Decreases the size of the critical region Increase the power of the test Has no effect on the hypothesis test

Model A:  Y= β_0+β_1 X+ε Model B:  Y= β_0+β_1 X+β_2 X^2+ε where Y = Earnings, X = Experience, and X Square dis Experience Squared     Suppose now that we’ve squared X and added that to the model.    Are the predictors significant in this model B? Explain.     Is this a good model? Compare this model B to model A. Which model should you use for predictive analytics purposes? Why?     Interpret the coefficients from Model B.     Can we interpret the coefficients from Model B as a causal parameters?

A researcher investigated the effects of cold on hypertension in rats by randomly assigning six rats to a 26oC environment and six to a 5oC environment and recording their blood pressures. (See data in picture) (a) Check the assumptions for running a t-test for the difference between the two treatment means. Which ones are satisfied and which aren’t? Explain.(b) Regardless of your answer to part (a), run a t-test for the difference between the two treatment means at the α = 5% level of significance. Specifically, we are interested in knowing if there exists sufficient statistical evidence to support the claim that low temperatures increase blood pressure in rats. Be sure to state the null and alternative hypotheses, calculate the appropriate test statistic, calculate the p-value, and state your conclusions.(c) Construct a t-interval for the difference between the blood pressures of the two treatment groups. Use 95% confidence.