In a study of income inequality in Los Angeles and Orange counties, researchers surveyed 100 households in each county and wanted to test the null hypothesis that the variance in household income was the same for these two counties. What type of statistical test should they use? O TMAX test OChi-squared test OF test Kolmogorov-Smirnov test OShapiro-Wilk testNPar Tests [DataSet]] C: \\Users\\gmb g\\Documents\\WFC. sav One-Sample Kolmogorov-Smirnov Test WFC N 77 Normal Parameters .b Mean 2.8365 Std Deviation 69369 Most Extreme Differences Absolute 138 Positive 138 Negative .086 Kolmogorov-Smirnov Z 1.208 Asymp Sig. (2-tailed) 108 a. Test distribution is Normal b. Calculated from data. Sn search W7. For the following observations: 0.3, 0.5, 0.8, 1.3, 1.7 You want to test whether the sample comes from a distribution with the following probability density function. 1 f(x) = (x +1)2 *>0 Calculate the Kolmogorov-Smirnov test statistic.2. What is the most plausible ranking of methods in causal inference by the methods' strength of internal validity, from strongest to weakest? (0.5 marks) O Regression discontinuity, randomized trial, difference-in-differences. O Difference-in-differences, regression discontinuity, randomized trial. O Randomized trial, difference-in-differences, regression discontinuity. O Regression discontinuity, difference-in-differences, randomized trial. O Difference-in-differences, randomized trial, regression discontinuity. O Randomized trial, regression discontinuity, difference-in-differences