In order to study whether IQ level is related to birth order, data were collected from a sample of 540 students on their birth order (Oldest/In Between/Youngest) and their score on an IQ test. The data collected in this study would be best displayed using:
what type of graph should I use?
Histograph or Bar Graph
To display the relationship between birth order and IQ scores for the 540 students, you can use a bar graph or a box plot.
1. Bar Graph: Use a bar graph if you want to compare the mean IQ scores for each category of birth order (oldest, in between, youngest). On the x-axis, label the three categories (Oldest, In Between, Youngest), and on the y-axis, display the average IQ scores. Then, for each category, draw a bar representing the average IQ score.
2. Box Plot: Use a box plot if you want to display the distribution of IQ scores for each category of birth order. Draw a box for each category (Oldest, In Between, Youngest), with the top and bottom edges of the box representing the upper quartile (Q3) and lower quartile (Q1), respectively. The line inside the box represents the median IQ score, and the lines extending from the box (whiskers) represent the range of data. Any points outside the whiskers represent outliers.
Both the bar graph and the box plot would allow you to compare the IQ scores across different birth orders and visually identify any patterns or differences. The choice between the two would depend on whether you want to focus on the summary statistics (bar graph) or the distribution of scores (box plot).