STAT 200 QUIZ 1 - Verified Answers Well Explained, Already Graded A+

1. (10 points) True or False. Justify your answers for full credit. (a) If all observations are identical in a data set, then the variance from this data set is zero. True: This is because the mean will be equal the values and no value will deviate from the mean. Therefore the variation or deviation from the mean will be equal to 0. (b) There may be more than one mode in a data set. Ture: Mode is the element with the highest frequency in a data set. (c) Suppose the minimum for a data set is 12. A careless assistant records it as 1.2, which is the only mistake in the record keeping. Based on this piece of information alone, we are not sure if this mistake will change the median of the data set. False: This value is the lowest in the data set, median being a value that is at the center of the data does not change. (d) The length of the running track in a high school is 400 m. The value 400 is from a discrete data set. False: The statement is telling the maximum length of the track, there is no data set. (e) Variance of a data set cannot be negative, but the standard deviation can be negative. False: Neither can be negative, Variance is the mean square of the mean deviations which is always positive. Standard deviation too is given by finding the square root of the variance. This study source was downloaded by from CourseH on :57:37 GMT -05:00 This study resource was shared via CourseH (For Questions 2 to 8) Choose the correct answer. Justify your answers for full credit. (2 points each) 2. A STAT 200 instructor is interested in the average weekly study time for UMUC STAT 200 students. She teaches two sections in Fall OL1, and randomly chooses 15 students from the first section and 18 students from the second section. This sampling method is called a. cluster b. convenience c. stratified d. systematic She studied a random number of students from each of the classes