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Delve into the world of sampling kiwis to determine median weights in New Zealand. Analyze findings to understand how sample size affects variability. Explore reliable sample sizes for population inferences. Learn through technology in a teaching environment.
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Kiwi Kapers 2 The impact of sample size…
Problem • I wonder what the median weight of New Zealand kiwis is?
Using technology… Remember we’re in TEACHING WORLD - in the ‘real world’ we wouldn’t be able to take lots and lots of samples to see what happens! • Sampling kiwis • Collecting the medians from repeated sampling
Analysis • For each sample size: • I notice that the sample median weights of kiwis for samples of size ___vary from ___ to ___ • I notice that the bulk of the sample median weights of kiwis for samples of size ___ranged from ___ to ___ • I notice that the median for the sample median weight of kiwis for samples of size ___ is ___ and that the median for the sample IQR is ___
Analysis • I notice that the variation of the median weights of kiwis ________ as the sample size _________. • For samples of size 15 the median weight ranged from ____ to ____, a difference of _____, • Whereas for samples of size 100 the median weight ranged from ____ to ____, a difference of ____.
Question? • What do you think will happen to variation in the IQR of the samples as we increase the sample size? • 12kiwipopsample2IQR
Conclusion As the sample size increases, the variation of the medians __________ the variation of the IQRs _____________ • What is a sensible and reliable sample size to use to make inferences about the population?
Conclusion Remember • Our best point estimate of the population parameter – the population median is our sample median • The estimates vary, even with n = 100 • It is better to provide a range of possible values for the parameter, based on our estimate, rather than stating one value
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