Exam 3: Measures of Variability

A score which falls at the 50th percentile must always be at the

For the following, use SPSS: A forensic psychologist was hired to test a group of police recruits and weed out those who might have any anti-social tendencies. The psychologist chose to test them on the MMPI2 and use their scores on the ASP Scale (Anti Social Practices) to identify any possible problems among the group. Their scores were as follows: 50,53,53,47,48,55,44,46,47,45,68,43,50,51. -Evaluate the distribution for Skewness

A researcher wished to evaluate the operating life of a certain brand of storage battery. A group of 30, brand-new batteries was selected and placed in 30 identical automobiles. The lights in each automobile were then turned on (without running the engines), and the length of time before the batteries were fully discharged (lights went out) was recorded. The scores, in hours, were: 15, 10, 20, 18, 18, 11, 11, 11, 11, 12, 12, 12, 10, 9, 9, 8, 9, 9, 11, 11, 11, 15, 12, 12, 12, 10, 12, 12, 15, 12. -For the following set of scores, calculate the standard deviation: 10, 8, 12, 3, 6, 7, 2, 10

A researcher gives IQ tests to a large group of adults, and discovers that the mean, median and mode all equal 100. The highest score in the group was 130 and the lowest was 70. Between IQ's of 75 and 125, 80% of the group was found, and 50% were found between IQ's of 90 and 110. The shape of the graphed distribution was mesokurtic. -The third quartile coincided with an IQ of

For the following, use SPSS: A forensic psychologist was hired to test a group of police recruits and weed out those who might have any anti-social tendencies. The psychologist chose to test them on the MMPI2 and use their scores on the ASP Scale (Anti Social Practices) to identify any possible problems among the group. Their scores were as follows: 50,53,53,47,48,55,44,46,47,45,68,43,50,51. -Evaluate the distribution for Kurtosis

A researcher wished to evaluate the operating life of a certain brand of storage battery. A group of 30, brand-new batteries was selected and placed in 30 identical automobiles. The lights in each automobile were then turned on (without running the engines), and the length of time before the batteries were fully discharged (lights went out) was recorded. The scores, in hours, were: 15, 10, 20, 18, 18, 11, 11, 11, 11, 12, 12, 12, 10, 9, 9, 8, 9, 9, 11, 11, 11, 15, 12, 12, 12, 10, 12, 12, 15, 12. -For the following set of scores, calculate the standard deviation: 8,9,10,12,10,10,16,11,24.

When the standard deviation has a negative value, then

The Children's Depression Inventory (CDI), developed from Beck's Depression Inventory is a self-report instrument with 27 sets of statements. Higher scores indicate higher levels of depression. Scores above 13 are said to indicate a Major Depressive Disorder (MDD) and few false positives have been reported. A random sample of 20 fifth grade students was selected and given the test. Their scores were as follows: 9,10,11,9,8,9,17,2,7,11,6,12,9,10,9,9,8,10,14,1. -Find the mean score for the group.

Of the following, indicate which is not a measure of variability

The higher the value of the standard deviation, the higher the

The only time the range may equal zero, is when

The first quartile coincides with the

A researcher gives IQ tests to a large group of adults, and discovers that the mean, median and mode all equal 100. The highest score in the group was 130 and the lowest was 70. Between IQ's of 75 and 125, 80% of the group was found, and 50% were found between IQ's of 90 and 110. The shape of the graphed distribution was mesokurtic. -The fifth decile coincided with an IQ of

The interdecile range lies between the

The variance is equal to

The standard deviation is a measure of

Specific points may be located on any distribution by using the

Of the following, which should not be calculated when the data are in ordinal form?

The higher the value of the mean, then the higher the value of the range.

The smaller the standard deviation