# My hypothesis is that people with siblings have a lower IQ than people without siblings. Also that people with lower IQ's have lower KS2 results.

Matthew Moorhouse

## Hypothesis

My hypothesis is that people with siblings have a lower IQ than people without siblings.   Also that people with lower IQ’s have lower KS2 results.

## IQ Levels

Using all the pupils available for KS4, I made a scatter graph showing how many siblings a pupil has against their IQ.   I saw several points, which were extreme so I deleted these from my graphs.   At this point I looked for a line of best fit but the line was almost horizontal so it would have been of no use.   After this I made a bar graph so I could see how many pupils had a given IQ.   This showed a concentration of pupils around the 100 – 104 area.

I produced several bar graphs so I could easily see any relation between sibling numbers and IQ.    The sort of relation I was looking for was that pupils with no siblings had a higher IQ than those with lots of siblings.

The number of pupils in certain sibling groups from KS4 was in some cases very low (11 in one case).   I had to use KS3 pupils to the number to 90 so each graph was a fair comparison and the results would be more accurate.   The last group of 6+ siblings only had 61 children in it.   These pupils were important because my hypothesis needs input from this high group.   The pupil count of this group was increased by ½ so there were 90 pupils in that group so they could be compared.

These bar graphs all showed a trend in the fact that they peaked in the same sort of area, which is 100 to 106 IQ in the 0 sibling and 6+ sibling groups,  and a double peak in the 1 – 5 sibling groups.   The double peak in this case is in the same sort of area,  91 to 109 IQ range.

I then averaged all the IQ’s for each sibling group so I could see the general trend when compared to each other and against the KS2 results (see Fig 4).   When I looked at ...