Answer to Question 1
Reliability is an indicator of a measure's internal consistency. A measure is reliable when different attempts at measuring something converge on the same result. When a measuring process provides reproducible results, the measuring instrument is reliable. Internal consistency is a term used to represent a measure's homogeneity and can be measured by correlating scores on subsets of items making up a scale. The split-half method of checking reliability is performed by taking half the items from a scale (e.g., odd-numbered items) and checking them against the results from the other half (even-numbered items). The two scale halves should correlate highly. Coefficient alpha is the most commonly applied estimate of a composite scale's reliability by computing the average of all possible split-half reliabilities from a multiple-item scale. This coefficient demonstrates whether or not the different items converge and ranges from 0 to 1, with values between 0.80 and 0.96 considered to have very good reliability. The test-retest method of determining reliability involves administering the same scale or measure on the same respondents at two separate times to test for stability.
Answer to Question 2
a
