1.) Tomorrow we will start class with a 7ish minute quiz: it will be just like Tuesday's HW
- Given a context determine if a value is a statistic or parameter, and provide the symbol
- Identify the sample
- Identify the population
- Know the difference between x-bar and mu, or between p-hat and p, or between Sx and sigma.
2.) Homework: -please use the sampling distributions applets linked below to complete the investigation we started in today's class:
- Understanding Sampling Distributions Questions (today's classwork):
- Exploring a Sampling Distribution for Proportions (questions 1-5)
- For the first five questions (what we started today) use the applet linked below:
- General things to notice:
- what is the shape of the sampling distribution?
- where is the center of the sampling distribution?
- Goal of questions 1-3:
- How does increasing sample size affect the shape and spread of a sampling distribution?
- How does decreasing sample size affect the shape and spread of a sampling distribution?
- Goal of question 4: which condition used with a sampling distribution for proportions would this connect to?
- Goal of question 5: what happens to the sampling distribution if we change the value of p?
- Change the value of p (probability of orange)
- Use a larger sample size
- Take many many samples--what changed with your sampling distribution?
- Focus on the center of the sampling distribution...
- Exploring a Sampling Distribution for Means (questions 6-8)
- The process is essentially the same as the one we outlined in class for a sampling distribution for proportions--but instead of calculating a sample proportion we'll calculate a sample mean (x-bar)
- Use the applet linked below:
- First, click begin and just play with the applet
- We can create two sampling distributions (the bottom two graphs) if we like, but we only need one
- Set the bottom graph to "None" in the drop down menu
- Set the 3rd graph to "means" (we want to make a sampling distribution for means)
- Set a sample size
- If you click "Animated" you'll see a sample being taken from the population (the black graph at the top); then, a blue bar pops down on to third graph--this blue bar is the sample mean being calculated, and so the blue graph will be a plot of the sample means--our sampling distribution
- You can click the "5" button to take 5 samples at a time and plot 5 sample means at a time rather than seeing everything animated.
- Or, click the "10,000" or "100,000" to see 10,000 blue bars plotted at a time
- What is the shape of the sampling distribution for means?
- Now, explore the effect of sample size...(question 7)
- Increase your sample size--how does increasing sample size affect the shape and spread of the sampling distribution for means?
- Lastly, let's see what happens if we change the the shape of the population (question 6)
- Change the shape using the drop down menu
- Create a sampling distribution with thousands of sample means
- What is the shape?
- Question 8: you can't actually use the applet to do this, so you'll have to hypothesize....
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