Question 1

Many human characteristics such as height are distributed so the majority of scores fall in the middle of the distribution, with fewer extreme scores. What do we call this type of distribution?

Accepted Answer

The distribution described in the question is a normal distribution, also known as a bell curve. This type of distribution is characterized by a symmetrical shape with the majority of scores falling in the middle and fewer scores at the extremes.

Question 2

A psychologist has collected some data representing the number of friends college students report they have. The data set follows: 6, 4, 3, 2, 7, 3, 8, 5. If the psychologist reports 3 as a measure of central tendency, which measure was used?

Accepted Answer

The mode is the number that appears most frequently in a data set. In this data set, the number 3 appears twice, more than any other number, making it the mode.

Question 3

According to DSM-IV-TR criteria, a person can only be diagnosed as mentally retarded if he/she has an IQ that is below approximately

Accepted Answer

According to DSM-IV-TR criteria, a person can only be diagnosed as mentally retarded if he/she has an IQ that is below approximately 70. It is important to note that the DSM-5 replaced the term "mental retardation" with "intellectual disability" and emphasizes that IQ scores should not be the sole factor in determining diagnosis.

Question 4

The cutoff score for mental retardation is approximately two standard deviations below the mean. If IQ scores were normally distributed, this would mean that approximately what percentage of the population would fall below this cutoff?

Accepted Answer

In a normal distribution, approximately 2.5% of the population falls below two standard deviations below the mean. However, since the question asks for "approximately," 2% is the closest option.

Question 5

IQ scores are derived from standard scores, and to calculate a standard score you need to know

Accepted Answer

To calculate a standard score, you need to know the mean and standard deviation of the distribution. IQ scores are typically calculated as standard scores, with a mean of 100 and a standard deviation of 15. Knowing the mean and standard deviation allows you to convert raw scores into standard scores, which can be compared across different populations and time periods. The mode and median are not used in the calculation of standard scores, and while the normal distribution is important for understanding the properties of standard scores, it is not sufficient for calculating them.

Question 6

Which child is most likely to show a significant change in IQ score if retested five years later?

Accepted Answer

Young children's IQ scores are more variable and less stable over time, so Ann, being the youngest, is most likely to show a significant change in her IQ score if retested five years later.

Question 7

Both the American Association on Intellectual and Developmental Disabilities and DSM-IV-TR define subaverage intellectual functioning in terms of

Accepted Answer

Both the American Association on Intellectual and Developmental Disabilities and DSM-IV-TR define subaverage intellectual functioning in terms of a score on an individualized intelligence test.

Question 8

In statistical calculations the square root of the variance is called the

Accepted Answer

The square root of the variance is the standard deviation, an important measure of the spread or dispersion of a dataset. Option B is not the correct term. Option C uses an unnecessary term "derived variation" and is also incorrect. Option D is incorrect as "standard variation" and "derived variation" are not correct terms.

Question 9

What is the mean and standard deviation of most intelligence tests?

Accepted Answer

Most intelligence tests are standardized with a mean of 100 and a standard deviation of 15. This means that scores are distributed around the mean of 100 with 68% of scores falling within one standard deviation above or below this mean. Therefore, choice C is the most appropriate answer.

Question 10

What system was used in early intelligence tests to compute an IQ?

Accepted Answer

In early intelligence tests, the IQ was computed by dividing the mental age by the chronological age, hence option C is the correct choice. This method was used in the Stanford-Binet Intelligence Scale, which was one of the first intelligence tests. Option A is incorrect because comparing scores to group norms is a method used to determine percentile rank. Option B is incorrect as dividing chronological age by mental age would result in a fraction, not an IQ score. Option D is incorrect because translating a score into standard deviations is a method used to create a bell curve and determine the distribution of scores, not to compute an IQ score.

Question 11

What do we call the midpoint of a frequency distribution?

Accepted Answer

The midpoint of a frequency distribution is the value that divides the distribution into two equal halves, which is the definition of median. Mode is the most frequently occurring value and may not be the midpoint. Norm is not a statistical term. Mean is the sum of all values divided by the number of values, and may not be the midpoint if the distribution is skewed.

Question 12

The AAIDD and the DSM-IV-TR agree that all of the following are criteria for what the DSM refers to as mental retardation EXCEPT

Accepted Answer

Neither the AAIDD nor the DSM-IV-TR include "significant perceptual impairment" as a criteria for mental retardation. The other criteria mentioned (significant limitation in intellectual functioning, significant limitation in adaptive functioning, and onset before age 18) are agreed upon by both organizations.

Question 13

The DSM-IV-TR criteria for mental retardation require a low IQ and deficits in adaptive functioning provided that they are

Accepted Answer

The DSM-IV-TR criteria for mental retardation includes the requirement that the deficits in intellectual and adaptive functioning must be present before the age of 18.

Question 14

A potential problem for the interpretation of IQ scores is the observation that IQ scores in general are rising across generations. The phenomenon is known as the

Accepted Answer

The phenomenon of rising IQ scores across generations is known as the Flynn effect, named after researcher James Flynn who first noted the trend. This effect can make it difficult to interpret IQ scores accurately over time, since a score that might have been considered high in one generation might be average or even low in the next.

Question 15

The American Association on Intellectual and Developmental Disabilities (AAIDD) uses a different term for DSM "mental retardation," which is

Accepted Answer

The AAIDD uses the term "intellectual disability" instead of DSM's "mental retardation" because it is more respectful and accurate. The other options are not officially used by the AAIDD to replace the DSM term.

Question 16

Your teacher uses the story of Chris Burke, who plays Corky Thatcher on Life Goes On, in an abnormal psychology class. What point is your professor trying to illustrate with this story?

Accepted Answer

The story of Chris Burke, who has Down syndrome, illustrates the fact that people with Down syndrome may have subaverage intelligence but this does not necessarily keep them from adapting well in life. Chris Burke has been able to achieve success as an actor and advocate despite his cognitive limitations. This challenges the stereotype that people with Down syndrome are unable to achieve much in their lives.

Question 17

The statistic in which the differences from the mean are squared (to eliminate negative numbers) before they are added together and divided by their total number is called the

Accepted Answer

The calculation described in the question is the formula for variance, so the answer is D. Options A and B are not accurate descriptions of this calculation. Option C refers to a different type of statistical measure.

Question 18

Twenty-nine-year-old Brenda has an IQ of 67, yet she finished fourth grade. She lives with her boyfriend, pays her bills with money she earns as a factor worker, and is able to live without supervision. What is Brenda's most likely diagnosis in terms of the DSM-IV classification of mental retardation (MR)?

Accepted Answer

Brenda is not considered to have mental retardation because, despite her low IQ, she demonstrates adaptive functioning by living independently, maintaining a job, and managing her finances.

Question 19

You are watching the film Rain Man and based on your course work in abnormal psychology recognize that an appropriate diagnostic category for the character Raymond portrayed by Dustin Hoffman is

Accepted Answer

The best choice is D, autism, as Raymond exhibits symptoms of restricted interests, social impairments, and repetitive behaviors that are characteristic of autism spectrum disorder. This is evident in his extreme insistence on routine, difficulty with social interactions, and fixation on certain topics. While options A and B may exhibit symptoms similar to what we see in the character Raymond in Rain Man, they do not account for the full range of his behaviors. Mild mental retardation is also an inadequate diagnosis as his abilities and behaviour are not consistent with mild intellectual disability.

Question 20

Al is 64 years old; he is currently a patient at a local hospital where a psychological battery revealed that he has subaverage intelligence and related deficits. Physicians and psychologists believe that his condition is the result of a degenerative brain disease. What is Al's most likely diagnosis?

Accepted Answer

Al's symptoms of subaverage intelligence and related deficits, along with the belief by medical professionals that his condition is caused by a degenerative brain disease, suggests a diagnosis of dementia. Delirium is a temporary condition typically caused by an underlying medical issue or medication, and emotional trauma or Asperger's disorder would not be consistent with Al's symptoms and medical history.

Quiz 15: Mental Retardation and Pervasive Developmental Disorders