Computer use Mrs. Causey asked her students how much time

Chapter , Problem R2.3

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Computer use Mrs. Causey asked her students how much time they had spent using a computer during the previous week. The following figure shows a cumulative relative frequency graph of her students responses. (a) At what percentile does a student who used her computer for 10 hours last week fall? (b) Estimate the median, Q1, and Q3 from the graph. Are there any outliers? 0 10 20 30 40 50 60 70 80 90 100 Cumulative relative frequency (%) 0 3 6 9 12 15 18 21 24 27 30 Hours per week This chapter focused on two big issues: describing an individual values location within a distribution of data and modeling distributions with density curves. Both z-scores and percentiles provide easily calculated measures of position for individuals. Density curves come in assorted shapes, but all share the property that the area beneath the curve is 1. We can use areas under density curves to estimate the proportion of individuals in a distribution whose values fall in a specified range. In the special case of Normally distributed data, we can use the standard Normal curve and Table A to calculate such areas. There are many real-world examples of Normal distributions. When you meet a new set of data, you can use the graphical and numerical tools discussed in this chapter to assess the Normality of the data. Describe the effect of adding, subtracting, multiplying by, or dividing by a constant on the shape, center, and spread of a distribution of data.