Smoker’s IQ A study was conducted in which 20,211 18-year-old Israeli male military recruits were given an exam to measure IQ. In addition, the recruits were asked to disclose their smoking status. An individual was considered a smoker if he smoked at least one cigarette per day. The goal of the study was to determine whether adolescents aged 18 to 21 who smoke have a lower IQ than nonsmokers. It was found that the average IQ of the smokers was 94, while the average IQ of the nonsmokers was 101. The researchers concluded that lower IQ individuals are more likely to choose to smoke, not that smoking makes people less intelligent.


What is the research objective?

Verified step by step guidance

1. Identify the main goal of the study by carefully reading the problem statement. Here, the study aims to explore the relationship between smoking status and IQ among 18-year-old Israeli male military recruits.
2. Note the specific groups being compared: smokers (those who smoke at least one cigarette per day) and nonsmokers.
3. Recognize that the study measures the average IQ scores for both groups: smokers have an average IQ of 94, and nonsmokers have an average IQ of 101.
4. Understand that the research objective is to determine whether smoking is associated with lower IQ scores in adolescents aged 18 to 21, i.e., to investigate if smokers tend to have lower IQs than nonsmokers.
5. Keep in mind the researchers' conclusion that the observed difference in IQ might be due to individuals with lower IQ being more likely to smoke, rather than smoking causing lower IQ. This highlights the importance of distinguishing correlation from causation in research objectives.

Key Concepts

Research Objective

The research objective defines the main goal or question the study aims to answer. It guides the design and analysis of the study, focusing on what the researchers want to understand or prove, such as whether smoking is associated with lower IQ in adolescents.

Correlation vs. Causation

Correlation means two variables are related, but it does not imply one causes the other. In this study, while smokers have lower average IQs, the researchers suggest that lower IQ may lead to smoking, not that smoking causes lower IQ, highlighting the difference between association and causality.

Operational Definition

An operational definition specifies how variables are measured or categorized in a study. Here, 'smoker' is defined as someone who smokes at least one cigarette per day, and IQ is measured by a standardized exam, ensuring clarity and consistency in data collection.