When faced with a problem or choice, humans can use two different strategies: "cognitive reflectivity," which results in slower responses and few mistakes, or "cognitive impulsivity," which results in quicker responses but also more mistakes. Depending on the individual, these two strategies are used differently. A pilot experiment was conducted on 22 right-handed individuals who were administered a cognitive reflectivity-impulsivity questionnaire, while recording voxel-based morphometry (regional gray matter density) in the ventral medial prefrontal cortex.

Based on the experimental designand the kind of data collected, which statistical test(s) should be used to determine whether there is an association between the cognitive strategy, cognitive reflectivity and the gray matter density of the ventral medial prefrontal cortex? Select all that apply!

A. One-way ANOVA

B. z-test

C. twosamplet-test

D. t-test of zero linear correlation

E. correlation coefficient (r)

The correlation analysis assumes that the measurements have a bivariate normal distribution in the population. Select all of the features that define a bivariate normal distribution.

A. A relationship betweenXandYthat is linear

B. Bell-shaped probability distribution in two dimensions rather than one

C. The frequency distributions ofXandYseparately are normal

D. A relationship betweenXandYthat is not linear

E. A cloud of points that is funnel shaped (wider at one end than the other)

F. The presence of outliers

G. EitherXorYhas a decidedly skewed distribution

Researchers want to survey the mass of American alligators in a certain region. They want to maximize the efficiency of this effort, and get as many measurements as possible. Capturing alligators, putting them on a scale, and releasing them involves risk and time. They decide to survey alligators from the air. In this manner they can measure the length of the animals. They want to use these measurements to estimate the mass of the alligators. They have access to data about length and mass of captive alligators.

Which statistical test should they use to evaluate the usefulness of this method?

A. Linear regression with t-test for significance of slope

B. ANOVA

C. Correlation analysis

D. Chi Squared Test