Probability and Statistics Pre Assessment questions and answers

In a class of 25 students, the following test scores were obtained: 31, 46, 49, 52, 55, 67, 68, 68, 69, 69, 71, 73, 73, 75, 75, 78, 79, 82, 84, 84, 85, 87, 91, 92, 97 Which statement is true about this distribution? CORRECT ANSWERS: The distribution is skewed to the left. In a class of 25 students, the following test scores were obtained: 51, 59, 59, 59, 67, 68, 68, 69, 69, 71, 73, 73, 75, 75, 78, 79, 82, 84, 85, 85, 87, 91, 92, 93, 93 A histogram of interval width 10 starting with the interval [50, 60] was constructed using the above data. Which statement is true about this distribution as depicted by the histogram? CORRECT ANSWERS: It is a unimodal symmetric distribution. In a class of 25 students, the following scores were received on a quiz: 3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 6, 6, 6, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9 For this distribution, what is the most appropriate measure of central tendency? CORRECT ANSWERS: Either the mean or the median The following 5-number summaries were obtained for two distributions, A and B: A 3.2 4.9 5.7 5.9 8.2 B 2.7 5.1 5.7 6.9 7.5 The distribution of A is skewed to the right, whereas the distribution of B is skewed to the left. How are the means of the two distributions related? CORRECT ANSWERS: The mean of A is higher than the mean of B. A study is conducted to determine if there is a difference in final exam scores in high school classrooms when different types of instruction are used. The two types of instruction included in the study are direct instruction and computer-based instruction. What are the explanatory (X) and response (Y) variables for this study? CORRECT ANSWERS: The type of instruction is the explanatory variable (X) and the test score is the response variable (Y).