Homework 1 Fall 2015 due Sept 23 in class.
1. Use the car data on the web and calculate the following using R:
Mean, standard deviation, first quartile of the price and mileage.
Plot price and mileage to see what type of relationship exists
Do a pie chart for the type of car.
2. Consider the following data from a single channel oligo study with 16 probe pairs
for a probe set. Calculate using the Wilcoxon Signed Rank Test (using Tau=.015)
the Detection and also calculate the Signal intensity using the Tukey Biweight
method.
MM1
2916.22
6369.49
1089.75
4705.19
956.33
3179.57
214.22
1455.74
666.33
3689.52
2296.42
9452.72
4263.36
3310.51
1765.97
1840.13
PM1
40154.0
3356.9
10972.0
10380.1
9379.7
9231.1
49444.2
35269.3
5727.2
50360.0
1531.5
5598.9
63598.8
13614.1
8586.3
15106.5
For n>10 we often use the large sample version of Wilcoxon Signed Rank Test to
find p-values.
The R code for Wilcoxon Signed rank test is:
wilcox.test(x, y = NULL,alternative=c("greater"),mu=0,correct=TRUE,
exact=NULL)
after you use the formula to create x=[(pm1-mm1)/(pm1+mm1)] -tau .
Do it by hand and also using R.
The Test Statistic is : Z = (obs-Emean/se),
where Emean=n(n+1)/4, se= sqrt(n(n+1)(2n+1)/24)
Use the z-table to calculate the p-value.
3.
Also put the above values in R and find:
a. Summary statistics for PM and MM
b. Mean, Standard Deviation and Interquartile Range for PM
c. Histogram of PM and MM
d. Plot PM against MM
Create a csv file and read it in and do the calculations.