Make-up exam. In a class of 25 students, 24 of them took an exam in class and 1 student took a make-up exam the following day. The professor graded the first batch of 24 exams and found an average score of 74 points with a standard deviation of 8.9 points. The student who took the make-up the following day scored 64 points on the exam.
(a) Does the new student’s score increase or decrease the average score?
(b) What is the new average?
(c) Does the new student’s score increase or decrease the standard deviation of the scores?
Infant mortality. The infant mortality rate is defined as the number of infant deaths per 1,000 live births. This rate is often used as an indicator of the level of health in a country. The relative frequency histogram below shows the distribution of estimated infant death rates for 224 countries for which such data were available in 2014.31
(a) Estimate Q1, the median, and Q3 from the histogram.
(b) Would you expect the mean of this data set to be smaller or larger than the median? Explain your reasoning.
Infant Mortality (per 1000 Live Births)
Fraction of Countries
0 20 40 60 80 100 120 0
0.1
0.2
0.3
0.4