Question

A developmental psychologist is interested in generating a model to describe and explain changes in IQ. To do this, he has developed a questionnaire that asks people to answer questions such that he has a measure of their IQ. Using this questionnaire, he is curious if participants’ cognitive abilities, as measured by the IQ scale, will change as people grow older. In order to test this, he collects data from a group of individuals (i.e., young adults) that range in age from 20 to 25 (n = 10). In addition, he collects data from a second group of participants (i.e., older adults) that range in age from 60 to 65.

DATA

Table 1. IQ scores from a young adult sample and an older adult sample.

	IQ Scores
Young Adults	106	123	102	127	95	105	87	106	105	93
Older Adults	111	128	130	122	116	109	138	110	92	104

QUESTIONS

1. What is this researcher’s hypothesis and what type of data is he using?
2. What type of research design is he using?
3. What is his independent and dependent variable?
4. Calculate the measures of central tendency for the young adults.
5. Calculate the measures of variability for the young adults.
6. Calculate the measures of central tendency for the older adults.
7. Calculate the measures of variability for the older adults.
8. What is the range in IQ scores for the young and older adults?
9. Using the mean as a simple model, describe the model fit for participants in the young adult group.
10. Using the mean as a simple model, describe the model fit for participants in the older adult group.

Answer 1