Question

A. Researchers examined the relationship between cola consumption and bone loss after fifty. One thousand women were randomly sampled, everyone's cola consumption was recorded over a two month period of time, and bone density measures were also recorded. Researchers found that the more cola consumed, the lower the level of bone density. They concluded that cola consumption leads to loss of bone density.

What type of study is this research and why?

Identify the variables.

Evaluation the internal validity.

B. Researchers examined differences in attitudes towards drinking between high school freshman and high school seniors. 400 students completed questionnaires that included information about drinking attitudes. The researchers found that older students maintained more liberal attitudes towards drinking than younger students. The researchers concluded that attitudes towards drinking and alcohol become more liberal with age.

What type of study is this research and why?

Identify the variables.

Evaluation the internal validity

Answer 1

(A)

(i)

This research is an observational study, because the researcher observes individuals without manipulation or intervention. There are no separate two groups: Research group with treatment and Placebo group without treatment. Records of 1000 women over a period of two months regarding coca consumption and bone density are only analysed.

: (ii)

Independent Variable: Cola consumption

Dependent Variable: Bone loss

(iii)

Internal validity: The study does not satisfy the Internal Validity because the following Confounding Variable is not avoided:

The inherent nature of bone loss after 50 years for women varies from individual to individual irrespective of whether they consume coca or not.

(A)

(i)

This research is an observational study, because the researcher observes individuals without manipulation or intervention. There are no separate two groups: Research group with treatment and Placebo group without treatment. The completed questionnaire by 400 students is only analyzed.

: (ii)

Independent Variable: Age

Dependent Variable: Attitude towards drinking

(iii)

Internal validity: The study does not satisfy the Internal Validity because the following Confounding Variable is not avoided:

The inherent nature of attitude towards drinking varies from individual to individual irrespective of the age of the person.