Download Stat 115 Homework Week 3

COURSE SCHEDULE- Week 3
2/3-2/6
2/03 Measuring Spread: Range, IQR, outliers, 5 number summary, mean absolute
deviation and standard deviation. How to find above values, what do they measure and
when to report what. (Changing variables by adding or multiplying by a constant and
their effect on the measures of center and spread)
Pre-class homework assignment for 2/06/03:
(2) Read : ActivStats Lesson 6- Comparing groups
6.1.3 Do Quiz!
6.2.1 Learn to create boxplots and summary statistics for the Rat Lifetime data. What
kind of boxplots have you created y by x or side by side?
6.2.2 Answer the questions: (1)What are the medians? (2)IQR's? (3)Why is a boxplot a
particularly good way to compare these groups?(4) What percentage of the RSD rats
lived longer than the ALD rats? (5)Approximately what percentage of ALD rats lived
longer than 900 days?
(6)Approximately what percentage of RSD rats lived longer than 900 days?
(7)Can you say that at least half of the ALD rats died sooner than 600 days?
(8) Can you say that at least 25% of the RSD group lived longer than 1200 days?
6.2.3 In each step record your answers to the questions. Step 1-2 has three questions,
and Step 4 has one question. Also record the name of the outlier in Step 2.
2/06 Lesson 6 : Comparing groups
Pre-class assignment for 2/10: (1) 5.1.1 This is the first appearance of a mathematical
model in our course. Record the information in the summary. Make sure to understand
that density curves are mathematical models NOT part of reality!!! They are used to
model histograms that on the other hand do record real data.
(2) 5.1.2. What do we use density curves for?
Record the numerical answers to Study Questions 1-4!
(3) 5.1.3 Do Quiz!
(4) Read ActivStats 4.4.3 Yes, no mistake, go back to
Chapter 4. Standardizing. How does standardizing change the shape, the mean and the
standard deviation of a distribution?
(5) 5.2.1 Where do you find the mean and standard
deviation of a normal density on its graph? What is the empirical rule? What will be
the mean and standard deviation of a normal density after standardizing ?
(6) 5.2..2 Quiz
(7) 5.2.3 How does the normal probability plot of a normally distributed variable look
like? How can you draw a normal probability plot in Data Desk?
Group Homework Due 2/17: Part (1) Lesson-6 ACT 1, MBS-1, MRB-1, MRB-3,
RMW-1,WEN-3
Part II. Each group has to bring to class a simple example of the use of statistics in
newspapers. You will show and describe the example in class. Make sure to pick
something that you understand. Be prepared to answer the W questions, note if the
answer is missing to any that could be a possible source of bias. Comment on how
reliable the information seems to you.