The more heterogenous the distribution of scores,
The larger the standard deviation
For any normal distribution, the 50th percentile corresponds to a z score of
0
Other things being equal, an alpha level of .05 should lead to a rejection of the null hypothesis
More often than when alpha is set at .01
Rejecting Ho when in fact it should have been accepted, causes
Type I error
When a difference is considered “statistically significant,” the most accurate interpretation of the finding is that the difference is probably
Not due to chance alone
The power of a statistical test, such as the independent t-test, can be increased by
All of the above
The only time the standard deviation may equal zero, is when
Every score in the distribution is the same
A scatter plot on which the array of points goes from upper left to lower right indicates
A negative correlation
When beta is increased (becomes numerically larger)
Power has decreased
The T score distribution always assumes a
Mean of 50, and a SD of 10
The mean of a given normal distribution of raw score is 200 with a standard deviation of 25. What percentage of scores is above 225?
16% of the scores
If the standard deviation for a particular distribution is 6, then the variance equals
36
The alpha level states the probability of being wrong when
The null hypothesis is rejected
Of the following correlation coefficients, which expresses the strongest association?
-.95
Which of the following terms best indicates a process variable (X) through which one variable (A) influences another (B) (e.g., it explains how A influences B)?
Mediator Variable
Which of the following types of data uses numbers or letters to label categories?
Nominal
A correlation coefficient of .80 yields a coefficient of determination of
64%
As the sample size increases, degrees of freedom
Increase
When the alternative hypothesis is accepted
The “chance” explanation, though not ruled out, is judged improbable
Which of the following does NOT contribute to a small effect size?
Use of uncontrolled multiple comparisons
When the standard deviation of the entire distribution of random sample means has been calculated, the resulting value is called
The standard error of the mean
The smaller the effect size, the greater the likelihood
Both a and d
The mean of a given normal distribution of raw scores is 200 with a standard deviation of 25. Between the raw scores of 150 and 250, there must be
95% of the scores
A researcher wishes to test the hypothesis that there is a positive association between IQ and musical ability. A random sample of 10 subjects was selected. The subjects were rank-ordered in terms of musical ability. A random sample of 10 subjects was selected. The subjects were rank-ordered in terms of musical ability. Then each subject was given an IQ test. Which of the following statistical tests is most appropriate to determine whether there is a significant relationship between IQ and musical ability in this situation?
Spearman r