What affects a persons ability to estimate?

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By Scott Rentell        Page         28/04/07

GCSE STATISTICS: COURSEWORK

‘WHAT AFFECTS A PERSON’S ABILITY TO ESTIMATE?’

Presentation of data, Calculations and Interpretation and Conclusions:

Now that I have collected all the data, I can now begin to analyse the results and find out whether either: age, intelligence or gender affect a person’s ability to estimate. To begin with I will investigate Age. By beginning with Age I can expand the investigation further by changing the variables one at a time. I will start simply by looking at the year groups and age groups. This will enable me to see whether theirs a difference. I will later go into more depth by comparing years. I will have clear views of the results by using a variety of graphs and charts regularly.

I have used the Average and Standard Deviation functions on Microsoft Excel to calculate these results. The answers have been rounded to the nearest 2 decimal places to make it clearer for readers to understand.

A bar graph is below to see the results more clearly and visually:

To get an even better view of the spread of results I’ve now put them in a box and whisker diagram, shown below. The calculations for the quartiles I found by using the function ’Quartile’ on Microsoft Excel. By doing this I’ll have a better idea of the dispersion of data these Year groups have.

 

Observations and conclusions:

- By studying the box and whisker diagrams I can see that both Year 7 and 8 have a large range of estimates between their third and fourth quartiles.

- From looking at the bar chart I can that the Year 11 mean average estimate is closest to the actual line (8.4cm). This makes it look as if Year 11 group are the best at estimating.

- Only the Year 11’s under estimated, the other Years all over estimated.

- The worst year group on average were the Year 7’s who estimated at around about 0.88cm more than the actual line.

- From the results, they show that as you get older, the spread of data decreases. Year 7’s Standard deviation was 2.90 compared to the Year 11 groups 1.56, almost half the number.

When looking back at my observations I conclude that the Year 11 group are better at estimating then any of the other years. From the fact that the Year 11’s data is less spread out and has a closer mean average to the actual length.

I’m now going to investigate the separate ages, 11-16. I’ll represent these in a bar graph for easy viewing and clear understanding:

Observations and conclusions

- From the bar graph I can see that Age 15 year olds have the closest mean average to the actual length.

- The worst age group on average were the 13 year olds who had a mean average of 9.19cm. On average they over estimated by 0.79cm.

- When looking at the standard deviation results, Age 16 had the closest range of estimates. This may be down to age and having a better experience at estimating lengths. From having such a close range of results, I can say that the 16 year old results are the most reliable in terms of accuracy.

- Finally, I noticed that the 12 and 13 year olds have extremely similar results. Their mean averages were only 0.04cm apart and their standard deviations were just 0.05 different.

To conclude my extended testing on Age, I will sum up the results and suggest what I think the data shows us. When I first began the investigation I expected the 15 and 16 year olds to have the closest mean average to the length. From now carrying out the investigation I can say I was correct. The results show that the 15 and 16 year olds were the closest. When looking at the other ages I can only note that the 11 year olds were closer than both the 12 and 13 year olds. This I didn’t expect because of the age difference and the experience advantage from the 13 year olds point of view.

Comparing Year 7 to Year 11

In this part of the investigation I am going to compare the whole of Year 7 and Year 11 to see whether age affects a person’s ability to estimate. I will only use the data for the Years and not change any other variables. This is to ensure the results are accurate and precise. To filter the data I shall use the Filter function on Microsoft Excel.

I shall show my results in different charts and graphs to produce a number of different views of the results. By doing this I’ll be able to have a more conclusive investigation of the two specified years. On each chart I’ll put the actual length to compare with the mean average for both years.

As well as finding the mean average, I will investigate the Standard Deviation and see whether the data for each year is compact or widely spread out. Having a low standard deviation would show the results to be more reliable, whereas a high standard deviation would mean not so reliable data has been collected.

I’ve used the results from the investigation earlier on, which involved all 5 year groups to calculate these results.

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On the following page a bar graph is shown to ensure the results are clear to understand:

Observations and conclusions:

- The bar chart above shows how the Year 11 group were closer on average to the 8.4cm length.

- The Year 7 group over estimated, whereas the Year 11 group under estimated.

- On average, there is a 1.17cm difference in the two sets of results. The Year 7 group were 0.88cm out from the genuine length. The Year 11 group were just 0.29cm away.

- The standard deviation results show ...

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