USA Today ’s annual survey of public flagship universities (Arienne Thompson and Breanne Gilpatrick, “Double-Digit Hikes Are Down,” October 5, 2005) indicates that the median increase in in-state tuition was 7% for the 2005–2006 academic year. A file titled Tuition contains the percentage change for the 67 flagship universities.
a. Produce a relative frequency histogram for these data. Does it seem plausible that the data are from a population that has a normal distribution?
b. Suppose the decimal point of the three largest numbers had inadvertently been moved one place to the right in the data. Move the decimal point one place to the left and reconstruct the relative frequency histogram. Now does it seem plausible that the data have an approximate normal distribution?
c. Use the normal distribution of part b to approximate the proportion of universities that raised their in-state tuition more than 10%. Use the appropriate parameters obtained from this population.
d. Use the normal distribution of part b to approximate the fifth percentile for the percent of tuition increase.