29 a B1 2 B1 for comparison statements such as D1 has data for H Suitable statements about the ages 18–11, which D2 does not; D2 has data for ages distributions with justification for why the 30–32, which D1 does not; D1 has a positive skew so it representations are from different has a low mode with a long right tail and D2 has a distributions. slight negative skew, so it has a higher mode but more consistency across a greater range oe Distribution 1 is for Africa, distribution 2 is b B1 B1 for observation of skewness and students’ for Europe, plus observations such as: comments on and perception of possible reasons such there is a peak at 21; distribution 1 is as: women in Africa tend to marry at a younger age; positively skewed; there is a more European women have better health care or careers constant frequency across the range for and so marry later; there is more gender equality and distribution 2 with more women marrying independent women in Europe oe older in distribution 2. 2 30 a Examples such as: B1 2 B1 for positive skew context where there is a long tail H positive skew income distribution to the right (higher values) and the bulk of the – distribution is to the left (lower values) negative skew age at death in B1 B1 for negative skew context where there is a long tail – developed countries. to the left (lower values) and the bulk of the distribution is to the right (higher values) The box will be shifted to be in line with B1 B1 for description of negative skew that includes a b the bulk of the distribution. It will veer comment on the distribution being focused to the right right for negative skew, left for positive (lower values) oe and central for no skew. c Suitable box plot for each distribution. B1 B1 for suitable positive skew box plot B1 B1 for suitable no skew box plot B1 B1 for suitable negative skew box plot Positive skew (long right tail, median to the left) 6
29 a b Suitable statements about the distributions with justification for why the representations are from different distributions. Distribution 1 is for Africa, distribution 2 is for Europe, plus observations such as: there is a peak at 21; distribution 1 is positively skewed; there is a more constant frequency across the range for distribution 2 with more women marrying older in distribution 2. B1 B1 2 B1 for comparison statements such as D1 has data for ages 18–11, which D2 does not; D2 has data for ages 30–32, which D1 does not; D1 has a positive skew so it has a low mode with a long right tail and D2 has a slight negative skew, so it has a higher mode but more consistency across a greater range oe B1 for observation of skewness and students’ comments on and perception of possible reasons such as: women in Africa tend to marry at a younger age; European women have better health care or careers and so marry later; there is more gender equality and independent women in Europe oe H 2 30 a b c Examples such as: positive skew – income distribution negative skew – age at death in developed countries. The box will be shifted to be in line with the bulk of the distribution. It will veer right for negative skew, left for positive and central for no skew. Suitable box plot for each distribution. B1 B1 B1 B1 B1 B1 2 B1 for positive skew context where there is a long tail to the right (higher values) and the bulk of the distribution is to the left (lower values) B1 for negative skew context where there is a long tail to the left (lower values) and the bulk of the distribution is to the right (higher values) B1 for description of negative skew that includes a comment on the distribution being focused to the right (lower values) oe B1 for suitable positive skew box plot B1 for suitable no skew box plot B1 for suitable negative skew box plot Positive skew (long right tail, median to the left) H 6
Higher_Skills_Statistics_MarkScheme_AQA.docx