Acher cat statistics and probability June 2023 Exam for Revision of NCLEX

1. Distinguish between the following terms as used in Statistics: a) Descriptive and Inferential Statistics. [2 marks] b) Stratified sampling and Systematic sampling. [2 marks] 2. The table below shows the distribution of students’ weights of first years taking an IT course. Weight 45-49 50-54 55-59 60-64 65-69 70-74 75-79 Frequency 7 14 18 11 5 9 4 Calculate: a) The standard deviation for the weight distribution [5 marks] b) Kelly’s coefficient of skewness and interpret the results. [6 marks] 3. Suppose a researcher wished to do a study on the ages of the top 35 wealthiest people in the world. The ages are listed in Forbes Magazine: 49, 57, 38, 73, 81, 74, 59, 76, 65, 69, 54, 65, 85, 49, 69, 61, 48, 81, 68, 37, 43, 78, 82, 43, 64, 67, 52, 56, 81, 77, 79, 85, 40, 85, 80. Construct a frequency distribution for the data. [5 marks] 4. The table below shows the distribution of students’ marks in a Statistics examination. Marks 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 Freq 3 4 7 9 5 14 12 9 12 Determine: a) The modal mark. [3 marks] b) If 70% of the students passed, what was the cut off for passing the exam? [3 marks] 5. From 108 randomly selected college applicants, the following frequency distribution for entrance exam scores was obtained. Scores 90-98 99-107 108-116 117-125 126-134 Frequency 6 22 43 28 9 On the same plot for the data, construct a histogram and a frequency polygon. [4 marks]