LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – STATISTICS

SUPPLEMENTARY EXAMINATION – JUNE 2008

ST 3901 - STATISTICAL APPLICATIONS IN BIOLOGICAL SCIENCES

Date : 28-06-08 Dept. No. Max. : 100 Marks

Time : 9:00 - 12:00

PART A

Answer all the questions. 5 X 2 = 10

  1. Write any two sources from which Primary data are obtained.
  2. Define biostatistics.
  3. Distinguish between Parameter and Statistic
  4. State any two applications of Statistics in Bio-Medical science studies.
  5. What measures are available in measure of central tendency?
  6. State any two properties of correlation.
  7. Declare any four characteristics of Normal distribution.
  8. Define Skewness.
  9. What are the advantages of Sampling?
  10. Mention any two uses of ANOVA while conducting Biological experiments.

PART B

Answer any FIVE questions. 5 X 8 = 40

  1. Distinguish between Diagrammatic representation and graphical representation of data. Illustrate any four Diagrammatic representations of data.
  1. Compute mean and median for the following data:

Age : 20-30 30-40 40-50 50-60 60-70 70-80 80-90

Number of patients : 15 19 11 25 22 10 5

  1. Calculate correlation coefficient for weights (kg) and heights (cm) of 10 patients in Maruthi hospital.

Weight : 83 99 63 71 65 70 69 56 66 88

Height : 185 180 173 168 175 183 174 164 169 205

  1. Explain various steps in involved in Hypothesis testing.
  2. The Weights (in Kg.) of 8 Obese Women before and after 12-weeks of VLCD(very low calorie diet) treatment are given in following table. Test whether these data provide sufficient evidence to allow us to conclude that the treatment is effective in causing weight reduction in obese women? Let a=0.05

Before : 104 96 103 105 100 87 85 72

After : 89 78 89 83 77 67 60 69

  1. The following data are the oxygen uptakes (milliliters) during incubation of a random sample of 15 cell suspensions.

14.0 14.1 14.5 13.2 11.2 14.0 14.1 12.2 11.1 13.7 13.2

16.0 12.8 14.4 12.9

Do these data provide sufficient evidence at the 0.05 level of significance that the population mean is not 12ml?

  1. In a random sample of 600 and 1000 men from two cities, 400 and 600 men are found to be illiterate. Do the data indicate at 5%level of significance that the population is significantly different in the percentage of literacy?
  1. A rifle club performed an experiment on a randomly selected group of first-time shooters. The purpose of the experiment was to determine whether shooting accuracy is affected by the method of sighting used: only the right eye open, only the left eye open, or both eyes open. Fifteen first-time shooters were selected and divided into three groups. Each group experienced the same training and practicing procedures with one exception: the method of sighting used. After completing training, each student was given the same number of rounds and asked to shoot at a target. Their scores are listed in the given table.

Method of shooting

Right eye Left eye Both eyes

12 10 16

10 17 14

18 16 16

12 13 11

14 20

21

At the 0.05 level of significance, is there sufficient evidence to reject the claim that the three methods of sighting are equally effective?

SECTION C

Answer any TWO questions (2 x 20 =40)

  1. In a research study, Drug dose in mg and heart-rate reduction values were observed from 10 patients.

Drug dose in mg / 0.5 / 0.75 / 1.00 / 1.25 / 1.50 / 1.75 / 2 / 2.25 / 2.50 / 2.75
Heart-rate reduction / 10 / 7 / 15 / 12 / 15 / 14 / 20 / 20 / 18 / 21

a)  Construct Regression equations and hence estimate the heart-rate reduction when drug dose is 095 mg

b)  Compute r2 and give your interpretation.

  1. a) The following table gives heights of boys and girls studying in a college. Calculate coefficient of variation for boys and girls and verify whose heights are more consistent?

Boys Girls

Number 400 100

Average Height 68 inches 65 inches

Variance 9 4

b) A study was designed to estimate the difference in diastolic blood pressures between men and women.

Men: 76 76 74 70 80 68 90 70 76 80

Women:82 90 68 60 62 60 62 72 68 74

Verify men and women are equal in diastolic blood pressures by using two sample independent t-test at 5 % level of significance.

  1. a) Two hundred adults who professed to love hot, spicy food were asked to name their favorite way to cool their mouth after eating food with hot sauce. Here is the summary of the sample:

Method / Water / Milk / Soda / Beer / Bread / Others / Nothing
Number / 73 / 35 / 20 / 19 / 29 / 11 / 13

Use chi-square test to test whether rinsing methods are equally effective and give your interpretation at 5 % level of significance.

b)  In a hospital 480 female and 520 male babies were born in a week. Do these figures

confirm the hospital that the male and female babies are born in equal number?

  1. A re-motivation team in a psychiatric hospital conducted an experiment to compare five methods for re-motivating patients. Patients were grouped according to level of initial motivation. Patients in each group were randomly assigned to the five methods. At the end of the experimental period the patients were evaluated by a team composed of a psychiatrist, a psychologist, a nurse and a social worker, none of whom was aware of the method to which patients had been assigned. The team assigned each patient a composite score as a measure of his/her level of motivation. The results were as follows:

Level of Initial motivation / Re-motivation method
A B C D E
Nil / 58 / 68 / 60 / 68 / 64
Very Low / 62 / 70 / 65 / 80 / 69
Low / 67 / 78 / 68 / 81 / 70
Average / 70 / 81 / 70 / 89 / 74

Perform 2-way ANOVA and interpret your results.

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