Blm5210 Bioinformatics Worksheet - 2015/16 printable pdf download

BLM5210 Bioinformatics

2015-16 Fall, Homework 1, Due Data: 19/10/2015

Q1: Import the Pima.tr data from the MASS package.

a) Evaluate the hypothesis that the population mean of diastolic blood pressure for Pima Indian women is

not 70.

b) Find the difference between the sample means of diastolic blood pressure for diabetic and nondiabetic

Pima Indian women. Is the difference between the means of diastolic blood pressure statistically

significant at 0.01 level?

Q2: We would like to investigate the effectiveness of various feed supplements (feed) on the growth rate (weight)

of chickens. In R-Commander, load the chickwts data set from the datasets package. (Click Data → Data in

packages → Read data set from an attached package.) Use boxplots and a plot of means to visualize the difference

between feed types. Use ANOVA to examine the effectiveness of feed supplements. Comment on your findings

and appropriateness of your assumptions.

Q3: In R-Commander, click Data → Data in packages → Read data set from an attached package, then select

the HairEyeColor data from the datasets package. The data include hair and eye color and sex for 592 statistics

students at the University of Delaware reported by Snee (1974). The first column shows different hair colors

(Black, Brown, Red, Blond), the second column shows different eye colors (Brown, Blue, Hazel, Green), and the

third column shows genders (Male, Female) of students. For each row, the last column shows the number of

students with a specific hair color, eye color, and gender.

(a) Use Pearson’s χ

test to evaluate the null hypothesis that different hair colors have equal probabilities. Use

Pearson’s χ

test to evaluate the null hypothesis that different eye colors have equal probabilities.

(b) Create a 4 × 4 contingency table where the rows represent different hair colors and the columns represent

different eye colors. Is there a relationship between hair color and eye color?

relationship between hair color and eye color.

Q4: A person has received the result of his medical test and realized that his diagnosis was positive (affected

by the disease). However, the lab report stated that this kind of test has false positive probability of 0.06 (i.e.,

diagnosing a healthy person, H as affected, D) and that the probability of false negative is 0.038 (i.e.,

diagnosing an affected person as healthy). Therefore, while this news was devastating, there is a chance that he

was misdiagnosed. After some research, he found out that the probability of this disease in the population is P

(D) = 0.02. Find the probability that he is actually affected by the disease given the positive lab result.

Blm5210 Bioinformatics Worksheet - 2015/16