Biometrics 301 Spring 2008 Exam 1 Name KEY Section Number The University of Maryland Honor Code will be strictly enforced Anyone suspected of cheating will be prosecuted to the fullest extent possible You may answer in pen or pencil but regrades other than mistakes in addition will ONLY be considered for tests completed in pen True or False Questions Please circle the one answer that best describes each statement Multiple Choice Questions Please circle the one letter that best answers the question being asked Each question worth 4 points unless otherwise indicated 1 The statement the sample mean was 10 mg is an example of descriptive statistics or inferential statistics 2 The entire collection of individuals or objects or events whose properties could be sampled and analyzed is a the sample b the population c the experimental unit a quantitative nominal b quantitative ordinal c qualitative nominal d qualitative ordinal a quantitative continuous b quantitative discrete c qualitative continuous d qualitative discrete 3 T shirt size small medium large or x large is an example of what type of variable 4 Number of people in a town is an example of what type of variable 5 List the 4 components of a good sample You do not need to describe the components just list them 6pts Independent Random No bias Covers the entire population 6 You create an insect trap that has an opening that allows insects up to 2 cm in size to enter the trap The insect population ranges in size from 0 5 cm to 10 cm in size If you use this trap to collect insects and know nothing else about the sampling procedure which of the 4 components of a good sample listed above would be of GREATEST concern Bias toward smaller insects 7 You decide to poll people in your district to find out if they are voting for or against the current Governor in the next election You go to a random sample of houses in your district At each house you get the answer to your question verbally from every adult present Which of the 4 components of a good sample listed above would be of GREATEST concern Independence of answers from people in same house 8 What is the key difference between judgement and random sampling 1 sentence Random sampling has to include an element of chance in determining which experimental units are selected 9 You ask 128 people what type of toothpaste they use every day Which of the following would be the best way to display the data IF you want to show the actual number of people using each type of toothpaste a circle graph showing frequency b circle graph showing relative frequency c d frequency histogram relative frequency histogram 10 T or F A general rule of deciding the number of classes to divide your data into for grouping frequency data is to use the equation classes 11 T or F Data distributions that are unimodal are always symmetric 12 If every value in your data set occurs at the same frequency then a b c the distribution is uniform the distribution is unimodal the distribution is j shaped 13 Which of the following is a measure of central tendency and is most impacted by outliers a standard deviation b mode c mean d median 14 T or F A normal curve is always unimodal symmetric and bell shaped 15 Which of the following does NOT provide information about measures of a data set s center and spread a Stem and Leaf Diagram b Box and Whisker plots c Pie Chart d Frequency histogram shown as a smooth curve 16 T or F For all normal curves the area under the curve between the mean and plus 1 standard deviation and the mean minus 1 standard is equal to 95 of the total area under the curve 17 T or F You have a group of college students to study For the men in your study you ask only their weight For the women in the study you ask only their height This is an example of a bivariate data set as discussed in class 5 10 15 20 25 30 35 Answer Questions 18 through 21 for the figure above If an answer can not be determined from the figure then write not applicable in the space Assume the graph above shows a normal distribution 18 What is the mean of the above distribution 20 19 What is the standard deviation of the above distribution 5 20 What is the largest value in the data set 35 or positive infinity 21 What is the name for this type of graph I m not looking for Normal Curve or a description of the type of shape the graph shows but the term for graphs shown in this manner Density Curve 2 6 10 14 18 22 Answer Questions 22 through 25 for the figure above If an answer can not be determined from the figure then write not applicable in the space 22 What is the mean of the above distribution Not applicable 23 What is the standard deviation of the above distribution Not applicable 24 What is the largest value in the data set 18 25 What is the name for this type of graph Box and whisker For the graph below circle the correct Plot letter for each of the 4 shown correlation coefficients Each answer is used once 2 pts each 26 27 28 29 26 C 27 A 28 D 29 B A 30 25 20 15 10 5 0 35 30 25 20 15 10 5 0 B 0 1 2 3 4 5 6 0 1 2 3 4 5 6 Answer the following questions 30 through 34 for the above graphs A and B 30 Which graph has the largest regression coefficient WE TALKED ABOUT THIS AS R2 A A and B are the same B 31 Which graph has the largest value for the slope A A and B are the same B 32 What graph as the largest value for the intercept A A and B are the same B 33 Which graph could be used to show that as temperature increases some degree F the size of the flower of some plant also tends to increase in mm A B Both A and B Neither A nor B 34 Which graph could be used to show that decreasing drug dose in ml causes the response to also decrease in mg kg A B Both A and B Neither A nor B 35 You find out that a company marketing videos to toddlers has completed research to show that using their educational videos is associated with an increase in toddler verbal capacity Which of the following issues of statistical deception would you MOST suspect a means were affected by outliers b data shown in confusing graphs c correlation is not causation d hidden information and or who did the study 36 T or F To show causation in a study of bivariate data requires completion of a controlled experiment 37 T or F If you know the R2 …