Bfw publishers the practice of statistics for ap 5e

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©BFW Publishers The Practice of Statistics for AP*, 5/e Test 1B Part 1 1. b 300 x 32% = 96 students. 2. d The vertical scale exaggerates differences in the number of champions of each breed. For example, 12 Mixed Breed dogs is only 4 more dogs than the 8 Australian Shepherds, not twice as many, as the graph suggests. 3. b The stem and leaf 9|0, representing 9.0%, is the second lowest value in the distribution. 4. d Q1 = 12.4% and Q3 = 14.3%. IQR is 14.3 – 12.4 = 1.9% 5. e Since the distributions is skewed left, the mean is less than the median, but I is too far to the left to possibly be the mean, so II is the mean and III is the median. 6. d The association is that a higher proportion of males are Republicans and a higher proportion of females are Democrats. 7. c A change in any value will affect the mean, but the median will not be affected by a change in the maximum value. 8. b The sum of the first 12 items is 12 x $3.25 = $39.00. The mean of all 13 items is ($39.00 + $6.50)/13 = $3.50. 9. d Standard deviation is a type of average of how far each day’s number of copies is from the mean number of copies.10. c 35 is Q1 and 61 is median, so 25% of the scores are in this range. 25% of 380 is 95. Part 2
12. (a) Histograms will vary with chosen bin width. One example at right. (b) Since the data is roughly symmetric, it would be best to use mean and standard deviation as measures of center and spread, respectively. 13. (a) Students may present a table of column conditional percentages, or a segmented bar graph (below and at right). (b)There is a strong association between age of viewer and the amount of violence they watched: the younger viewers had the highest proportion of “high-violence” viewers, and the older viewers had the lowest proportion of “high-violence” viewers. Those in the middle-aged range had an intermediate proportion of “high-violence” viewers. Violence Watched 16-34 35-54 55 and over Low 30.8% 44.4% 75% High 69.2% 55.6% 25%
©BFW Publishers The Practice of Statistics for AP*, 5/e Test 1C Part 1 1. e Age and number of years at current address are quantitative, gender, favorite subject, and college intent are categorical. 2. d We tend to make comparisons based on area even when height is the intended comparator. 3. e Since there are now only four people in the room, the median is the average of the second and third highest ages. We know that the third oldest is 30, but without knowing the second oldest, we can’t determine the median. 4. e “Fairly-priced” is about 40% of the distribution and the percentage for “Don’t know” is very low. This reduces the choices to (a) and (e).

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