The 2019–2020 northwestern Syria offensive, codenamed "Dawn of Idlib 2", was a military operation launched by the armed forces of the Syrian Arab Republic, Russia, Iran, Hezbollah and other allied militias against Syrian opposition and allied fighters of the Syrian National Army, Hayat Tahrir al-Sham, Rouse the Believers Operations Room, the Turkistan Islamic Party, and other rebel and Salafi jihadist forces in Idlib and surrounding governorates during the Syrian Civil War. The offensive began on 19 December 2019 and saw Russian-backed pro-government forces clash with Turkish-backed opposition groups along with leaving 980,000 civilians displaced. By February 2020, pro-government forces had encircled several Turkish observation posts that had been established throughought Idlib. On 27 February, after intermittent deadly clashes between Turkish and Syrian forces, Turkey formalized its military intervention and announced the beginning of Operation Spring Shield, aimed at pushing back Syrian government forces to pre-offensive frontlines. On 5 March 2020, a meeting took place between Turkish President Recep Tayyip Erdoğan and Russian President Vladimir Putin. They agreed on a ceasefire beginning on 6 March that established a 6 kilometer secure corridor along the M4 Highway. The ceasefire also called for joint Turkish–Russian patrols along the highway beginning on 15 March.

A statistic (singular) or sample statistic is any quantity computed from values in a sample that is used for a statistical purpose. Statistical purposes include estimating a population parameter, describing a sample, or evaluating a hypothesis. The average (aka mean) of sample values is a statistic. The term statistic is used both for the function and for the value of the function on a given sample. When a statistic is being used for a specific purpose, it may be referred to by a name indicating its purpose. When a statistic is used to estimate a population parameter, is called an estimator. A population parameter is any characteristic of a population under study, but when it is not feasible to directly measure the value of a population parameter, statistical methods are used to infer the likely value of the parameter on the basis of a statistic computed from a sample taken from the population. For example, the mean of a sample is an unbiased estimator of the population mean. This means that the average of multiple sample means will tend to converge to the true mean of the population.. In descriptive statistics, a descriptive statistic is used to describe the sample data in some useful way. In statistical hypothesis testing, a test statistic is used to test a hypothesis. Note that a single statistic can be used for multiple purposes – for example the sample mean can be used to estimate the population mean, to describe a sample data set, or to test a hypothesis.