Simulation Question

In question 2bii. of the 2016 paper for the Probability Concepts standard, would someone be so kind to give me clarification on what the answer means, and even the question?

I am not that familiar with simulations. I understand that the simulation would provide us with a model estimate and would show sampling variation. But I do not understand why they assume 86% accuracy rate. What does it mean to assume a 86% accuracy rate when carrying out the simulation.

I would really appreciate clarification on how this simulation would be carried out, and how it could determine whether the person has a lower/higher accuracy rate than 86%.

Hi there - thanks for your query - although our forums are not open until next month, we thought it might be helpful to provide you a response.

Please let us know if you require more information. We’d also love to hear other people’s thoughts.

The Company have seen that one of the observers got 30 out of 42 of their guesses correct (which is 71.4%). This is lower than the 86% (or 36.12 out of 42) accuracy rate that they have worked out for all observers in general.

The key here is that it is every observer will have a different accuracy rate as each person is different and each situation is different and this is what sampling variability is all about.

86% is the expected or average accuracy rate. It would be good to run a simulation with an accuracy rate of 0.86 (this can be used as the probability that they will guess the right age range for each group of 42 shoppers) to see the range of possible accuracy rates that could happen due to sampling variability.

Think of the results in a dot plot: you would expect to see the accuracy rates generated in the simulation to be mostly grouped around the expected rate of 0.86 with fewer dots the further away you get from this expected value.

After running the simulation to see this range of generated accuracy rates, the company can see if this observer’s rate is likely or not. If it is not a likely accuracy rate, then this suggests that the observer probably does have a lower than expected accuracy rate.

This answer makes a lot of sense, and I appreciate how well and detailed you made the answer. I think the comparison to the dot plot is what made everything click. Thank you for taking the time to write this response, despite the forums being closed.

May I ask when the forums will reopen so that I can post more questions?

Thanks a lot!

Fantastic that you found the response informative :slight_smile: We anticipate re-opening the forums around 21st September and look forward to discussing more NCEA topics with you then!

Great! Looking foward to that as well.
Another quick question, is there a way to change my name because I would like to be anonymous?

Try going to the top of the forum bar where there is a round circle with the letter of your name in it. If you click on the circle, then go to the ‘preferences’ button - you should be able to edit your name. If this is not possible, please let me know and I will check with our team.

Thanks for the reply. I tried what you said but it is not working. It only allows me to change my profile picture or my email address and not my name. If there is another way, please do let me know :blush:Thanks

I was just wondering if there is any luck with changing my name on studyit?


If you email and let us know your preferred user name we can give it a go :slight_smile:

Ok Thx, doing it now

Thank you . All Sorted now.