PubHlth 540 Introductory Biostatistics 1 Unit 1 - Summarizing Data Week #1 - Practice Problems Due: Monday September 15, 2008 1. For each of the following variables indicate whether it is quantitative or qualitative and specify the measurement scale that is employed when taking measurements on each: (source: Daniel, page 12, problem #6.) a) Class standing of members of this class relative to each other b) Admitting diagnosis of patients admitted to a mental health clinic c) Weights of babies born in a hospital during a year d) Gender of babies born in a hospital during a year e) Range of motion of elbow joint of students enrolled in a university health sciences curriculum f) Under-arm temperature of day-old infants born in a hospital 2. Using the data below (source: Daniel, 6th edition page 30, problem 2.3.5), 7 10 12 4 8 7 3 8 5 12 11 3 8 1 1 13 10 4 4 5 5 8 7 7 3 2 3 8 13 1 7 17 3 4 5 5 3 1 17 10 4 7 7 11 8 BY HAND … a. Construct a stem and leaf display. b. Construct a frequency table with columns for frequency, relative frequency, cumulative frequency, and cumulative relative frequency. c. Construct a histogram. d. Construct a frequency polygon wk1_practice.docPubHlth 540 Introductory Biostatistics 2 3. Data were recorded on the age in years and height in cm of 20 high school students in a classroom. ______________________________________________________________ Females Males Age Height Age Height _______________________________________________________________ 15 170 15 185 15 154 16 183 16 160 16 174 15 159 15 183 15 156 15 173 15 153 15 173 16 166 15 178 16 163 14 167 15 167 15 177 15 151 16 171 _______________________________________________________________ BY HAND a. Create a frequency table for age, with columns for frequency, relative frequency, cumulative frequency, and cumulative relative frequency. b. Create a histogram for age. c. For each sex, create a stem-and-leaf display for height. What does a comparison of the displays suggest about the students? d. For each sex, create histograms for height using the same scale. 4. Let x1=3, x2=1, x3=4, and x4=6 a. Express the following sum in sigma notation and evaluate numerically. (x1 + x2 + x3 + x4)2 b. Express the following sum in sigma notation and evaluate numerically. x12 + x22 + x32 + x42 c. Evaluate the following numerically. Σ (Xi – 1)2 for i=1…4. d. Evaluate the following numerically. Σ 3Xi for i=1…4.