Let x and y denote the weights in grams of male and female gallinules, respectively. assume that x is $n(\mu_x, \sigma^2_x)$ and y is $n(\mu_y, \sigma^2_y)$. suppose there are n = 16 observations of x and m = 13 observations of y. we are interested in testing the null hypothesis $h_0: \mu_x=\mu_y $ against the one-sided alternative hypothesis $h_1: \mu_x > \mu_y $. let $\alpha = 0.01$.(assume that the variances are equal.)

let us say we suspect that that equality is not valid. thus, use the test proposed by welch.

what is the value of welch's test statistic?

Agroup of student volunteers participates in a study designed to assess several behavioral interventions for improving output in a repetitive task. prior to the beginning of the study, all volunteers unknowingly observed, and their output is measured. at the beginning of the study, prior to any intervention, the volunteers perform the same task under the observation of a study administrator, and their overall output increases. which of the following terms describes this phenomenon? a. simpson's paradox b. hawthorne effect are d. novelty effect d. pygmalion effect e. observer-expectancy effect