The phosphate are found in the ribose-phosphate backbone of DNA. Phosphate links the sugars, called deoxyribose and from which DNA or deoxyribonucleic acid gets its name, to make up the backbone of each strand of DNA. Each sugar is linked to the next by a phosphate group. RNA, made up of ribose rather than deoxyribose, or both sugars, is similarly negatively charged.
Interquartile is a term used in statistics. In particular, the interquartile range is one measure of the spread of a distribution. A distribution is a record of the values of some variable. For example, if we found the incomes of 100 people, that would be the distribution of income in our sample.
1 The interquartile range is equal to the difference between the upper and lower quartiles: IQR = Q3 â Q1.  It is a trimmed estimator, defined as the 25% trimmed mid-range, and is the most significant basic robust measure of scale.