Together:
binomial with percentage different than 0.5
binomial mean and sd
example problem
...and then...
When you finish question one (all parts) , please e-mail it to me post haste (right then) so I can check and have a quick meeting with you.
Question 1:
a) When looking for outliers and normality, there are three graphs we tend to make. What are they?
b) For each of the answers above, how comfortable are you in making them in r?
c) We use two different tests to check for outliers. What are they and in what circumstances do we use them?
d) Give me a run down on the basic steps we check when looking for normality in a set of numbers.
e) What notes do you have/need for r code?
f) What notes do you have/need for the statistical methods we have learned in class?
Question 2:
Here are the IQ test scores of 31 seventh-grade girls in a Midwest school district. This is an SRS over the whole district. The sd of IQ scores is known at 15 for this population.
114 100 104 89 102 91 114 114 103 105 108 130 120 132 111 128 118 119 86 72 111 103 74 112 107 103 98 96 112 112 93
check the data to make sure there are no major departures from normality. If there are, decide whether to remove them or not.
estimate the mean IQ score for all seventh-grade girls in the school district? Give you answer at the 99.7% interval.
explain specifically what the range you got in the question above this represents.
Which aspects of this question gave you the most trouble.
Question 3:
My friend claims that he is amazing at making basketball free throws. In fact, he claims that he makes 80% of all free throws. As such, and being the person that I am, I set up an experiment. I have him attempt 20 free throws in a row. He makes 12 of them.
What are the chances that someone who has a success rate of .8 would make 12/20?
What are the chances that someone who has a success rate of .8 would make 12 or less?
Explain the difference in the two questions asked above?
Question 4:
Consider the average amount of sap from a single maple tree is approximately N(10, 2.1) for a given sap run (i.e. spring), where the measurement is given in gallons.
between what values will 95% of all trees give sap?
80% of all trees will give below what amount of sap?
What percentage of trees will give between 8 and 13 gallons?
A tree gives 7 gallons of sap. What is this tree's Z-score?
Question 5:
On page 191 is a list of spring break destinations (oh la la).
Are you comfortable in finding random numbers in r?
Find a random selection of five of the 28. Give the code and show the selection.
Why do we need to use random selection for these numbers?
Extension:
Due in class (Monday, March 26):
Read section 6.1. Questions we will attack in class (bring them with you, no need to turn them in):
We've been saying that 95% confidence is 2 standard deviations. The book now says "Actually, 1.960 is 2 standard deviations". That's frustrating, isn't it?
Describe what a confidence interval is, describe why we call it a confidence interval, and explain what we do with a confidence interval.
Explain what z* is and how it relations to the old fashioned Z score we used before.
6.13, 6.14, 6.22