Delays, lack of resources, losses, and failures are all sources of ______ identified by your text

In the "Johnny and Jimmy" study by McGraw, Johnny (who learned skating earlier than Jimmy) had difficulties skating when he was 3 years of age. McGraw credited this finding to

A. boredom on Johnny's part B. attitudinal differences; Johnny had become reckless while Jimmy was cautious C. Johnny's learning to ride the tricycle; the two tasks could not be maintained at the same time D. inhibition

In a stratified sample subgroups in the general population need not be represented in the same proportion in the experimental sample

a. true b. false