Multiple choice. Support your Answers

4. Consider the result of a fictional Stat 100 final exam taken by 120 students, as given in the following relative frequency distribution: Grade Less than 50 50-59 60-69 70-79 80-89 90-100 Cumulative Frequency 15% 10% 30% 25% 15% 5% How many students received at least a 70 on this exam? a) 54 b) 45 c) 25 d) 30 e) 66 5. According to the empirical rule, approximately what percentage of normally distributed data lies within one standard deviation of the mean? a) 59% b) 68% c) 72% d) 95% e) 99.7% Note: Questions #6-#8 are based on the following sample of ages (in months) of 18 children at a day care: 36, 42, 18, 32, 22, 22, 25, 29, 30, 31, 19, 24, 35, 29, 26, 36, 24, 28 6. The median age of the children is... a) 29 b) 28.2 c) 30.5 d) 28.5 e) 31 7. The interquartile range for this data set is... a) 8 b) 12 c) 16 d) 20 e) 24 8. The standard deviation of the age of children is... a) 41.24 b) 11.33 c) 10.20 d) 6.42 e) 6.24Note: Questions #9-#12 are based on the following grouped frequency table of the income, x, of 30 employees at a local small business (in $1000s). Income $26