12. The components of the OLS variances Under assumptions MLR.1 through MLR.5, conditional on the sample values of the independent variables, the variance of B, under OLS is: Var () where o - the variance of the error term SST, - the total sample variation of z, RỆ - the R-squared from a regression of z, on all of the other explanatory variables, along with an intercept parameter The variance of By ▼ as R increases. decreases For the given mode e following would lead to a reduction of the sampling variance of 37 increases O Adding al variable that is equal to 5 + z, O using the same data set with the same number of observations O Adding irrelevant explanatory variables to the model that are correlated with zy O Choosing an explanatory variable za that is uncorrelated with the other explanatory variables in the model

On average, Upstate Chevrolet sells 20 cars each week, with a standard deviation of 2. How many cars sold represents 2 standard deviations above the mean? Answer     How many cars sold represent 1 standard deviation below the mean? Answer     Approximately 68% will fall between Answer   and Answer   .   Approximately 99.7% will fall between Answer   and Answer   .   What is the probability that the car lot will sell at least 18 cars? Answer   %   What is the probability that a car lot will sell at most 26 cars? Answer   %

1. A study compared the number of tree species in unlogged forest plots to similar plots logged 8 years earlier. Independent random samples of both logged and unlogged plots were analyzed and the number of tree species was recorded. Tables 1 and 2 present the Shapiro-Wilk normality test for both types of forest plots and the Independent Samples t-test results. Use the information presented in these tables to answer the questions. Table 1: Tests of Normality Tests of Normality Kolmogorov-Smirnov Shapiro-Wilk Forest Plot Statistic df Sig. Statistic df Sig. Tree_Species Logged .181 12 .200 .936 12 .444 Unlogged .110 14 .200 .945 14 .480 *. This is a lower bound of the true significance. a. Lilliefors Significance Correction Table 2: Independent Samples Test Independent Samples Test Levene's Test for Equality of Variances t-test for Equality of Means 95% Confidence Interval of the Difference Mean Std. Error F Sig. t df Sig. (2-tailed) Difference Difference Lower Upper Equal variances…

The following output comes from regression using the actual HW9 scores and the Final test scores from intro stats one semester.    Sample size: 50R (correlation coefficient) = 0.3658R-sq = 0.1338Estimate of error standard deviation: 10.36256Parameter estimates: Parameter Estimate Std. Err. DF T-Stat P-Value Intercept 43.558118 11.1716 48 3.899 0.0003 Slope 0.360048 0.132225 48 2.723 0.009 Assume no assumptions are violated. Form a 87% Confidence interval for how much your final is supposed to increase for each problem done on homework 9.Use 5 decimal places