Exam 10: The Hypothesis of Difference

When a difference is considered "significant", it indicates that the difference is probably

The higher the likelihood of rejecting null when null really should be rejected, then

The larger the effect size, the greater the likelihood of rejecting the null hypothesis.

The sign of the t ratio only becomes important to the statistical decision when

When pairs of samples are selected from two separate populations, the mean of the distribution of differences is assumed to be

Student's t can only be used with ordinal data.

When an inferential statistical test such as the t test is showing significant results, then the effect size must be large.

Whenever the mean of the distribution of differences equals zero, then one can be fairly safe in concluding that

For a given t value, the likelihood of rejecting null increases when a two-tail, rather than a one-tail, t value is applied.

The true standard error of difference is equal to the standard deviation of the entire sampling distribution of differences when all the sample pairs in the population have been measured.

Since psychopaths account for a quarter of all prisoners in the United States (and for as much as 50% of all violent crime) researchers have been examining the personality traits that may play a role in this condition. Tow groups of inmates, half diagnosed by Psychiatrists as psychopathic and the other not so diagnosed were given the IRI (Interpersonal Reactivity Index as a measure of empathy). The scores, converted to T scores were as follows: Psychopaths: 35,40,28,44,45,48,42,38,40,44. Non-Pychopaths: 52,60,50,48,55,50,54,55,44,40. -Find the means for each group.

If an independent t ratio is to be calculated for a two-group design, 20 subjects in each group, then the degrees of freedom equal

Power can be defined as

When the degrees of freedom reach infinity, the t distribution

If all the possible pairs of sample means were obtained from a single population, the mean of the distribution of differences would be

When the null hypothesis is rejected, then

A group of 20 violent drug abusers, all of whom had committed homicide while under the influence of a psychostimulant, was selected from the population of a certain prison. Half the men had been cocaine abusers while the other half had been on methamphetamines. All were abstinent at the time of testing. The men were tested on the CAQ (Clinical Analysis Questionnaire) and their Factor Q1 scores were compared (Factor Q1 includes Radicalism, Hypochondriasis and Boredom & Withdrawal). Their scores, converted to T scores, were as follows: Cocaine Group: 65,58,65,62,60,61,70,71,68,75. Methamphetamine Group: 60,53,52,55,54,59,62,60,60,56 -Identify the dependent variable.

Student's t demands at least interval data.

For the independent t test, the hypothesis of "no difference" is called the

When all the possible sample pairs have been selected from a single population, the mean of the distribution of differences is expected to approximate zero.