Stat 101-Midterm Exam Notes

STAT 101-MIDTERM EXAM NOTES 6. How many of the students surveyed eat at least four servings of fruits and vegetables daily? 8+3+1=12 7. What percentage of the students surveyed eat no more than three servings of fruits and vegetables daily? 62.5% (10+5+4+1=20/ 1+4+5+10+8+3+1=32 hence 20/32 = 62.5%) 8. What proportion of the students surveyed eat exactly five servings of fruits and vegetables daily?3/32=.0937 round to .094 Number of calls made Frequency 1-4 16 5-8 11 9-12 5 13-16 3 17-20 1 9. How many of the people surveyed make fewer than nine phone calls daily? 16+11=27 10.How many people were surveyed? 16+11+5+3+1=36 Interpreting the Histogram The center of the distribution is its median - the value that divides the distribution so that approximately half the observations take smaller values, and approximately half the observations take larger values. The spread (also called variability) of the distribution can be described by the approximate range covered by the data. Outliers are observations that fall outside the overall pattern. Choose the best description of the data used to generate this histogram (note that the horizontal axis has no scale, so you will make your choice based solely upon the histogram's shape): 11.Results of rolling a six-sided die 1,000 times (The bulk of deaths from trauma (accidents, suicide, drug overdose, etc.) happen at a younger age, and fewer at an older age. Therefore, we expect the distribution of age of death from trauma to be skewed right.) 12. Cholesterol levels of 1,000 adults (This histogram's distribution is symmetric—unimodal—the highest bars are in the middle, with the rest sloping symmetrically down on both sides. We'd expect the cholesterol levels of adults to consist of a few very low numbers and a few very high numbers, with most in the middle.) 13. Shoe sizes of 1,000 men and women (The histogram's distribution is symmetric—bimodal, since there are two peaks. Since the shoe sizes of women are usually smaller that those of men, we'd expect two places where the bars are higher.) 14.Prices of 1,000 California homes (This histogram has the bulk of the data on the left, and thus is skewed right. We'd expect a few mansions that are worth millions to make this distribution skewed right.) 15. SAT Math scores of 1,000 future engineers and scientists (The bulk of the data in this histogram is on the right, so its distribution is skewed left. The