Each person in the group must answer question one on a sheet of paper and turn it in to me. I will then call you for appointments throughout today and tomorrow.
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) When working in r, what resources do you utilize to make sure you are using the right code?
f) When doing math, what resources do you use to make sure you are doing the right statistical methods?
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 as a group the most trouble?
Question 3:
On page 191 is a list of spring break destinations (oh la la).
Are you comfortable in finding random numbers in r?
We want a random selection of hotels to let us know what the different rates are for a night at one of the spring break resorts.
Find a random selection of ten of the 28. Give the code and show the selection.
Why do we need to use random selection for these numbers?
When you actually do this, you call the ten you chose and they give you the following rates:
$88, $150, $107, $111, $49, $78, $98, $249, $165, $99
Give me a 95% confidence interval for the true average for all of the resorts. Assume that the population sd=25
Question 4:
On page 74 is some information on hatchback cars (I think we've used this data before). Assume that the data is a SRS and that there is no reason to remove any outliers.
Give a 90% confidence interval for hatchbacks and a 90% confidence interval for the sedans. sd of the car population is about 6.
What numbers were different in the two computations you just did?
Are we sure that the MPG for hatchbacks is better (higher) than the MPG for sedans? In a brief yet complete paragraph, explain your reasoning for the decision that you've made. Make sure you use the information you got in the first part of this question.
Question 5:
If a random number generator truly is random,if it sampling from 0 to 100, it should tend towards having a mean of 50 and a population sd of 28.87.
Use r and create a list of 50 random numbers.
if stuck, try sample(0:100, replace=TRUE)
Use those numbers to determine whether or not you think the generator is truly random or not. Be sure to explain each step as you do it.
Question 6:
The grades on my quizzes over the course of my teaching career have been roughly normal with N(83, 9)
Explain what N(83, 9) means.
What is the z-score for a person who scores a 91?
What percent of people score a 95 or higher?
What percent of people fail my quizzes?
What percent of people score a B?
Question 7:
Find a set of data online. Make a visual that helps represent that data in a positive way. Make your graphic as fair and balanced as possible (don't use 3d, for example).