Anders Gustaf Ekeberg specifically, tantalite from Kimito, Finland and yttrotantalite from Ytterby, Sweden. Ekeberg named the new element after the mythical Ancient Greek demigod Tantalus who, according to legend, was condemned to eternal frustration when he had to stand in water up to his neck, but the water receded as he attempted to drink. Ekeberg suffered from poor health throughout his life. During his childhood a severe cold had impaired his hearing, which was further weakened over the years, so that it hindered his teaching activities. Subsequently, a gas explosion blinded him in one eye. Ekeberg was portrayed by his friends and students
Item response theory with higher math ability are more likely to get a math item correct. The exact value of the probability depends, in addition to ability, on a set of "item parameters" for the IRF. For example, in the three parameter logistic model (3PL), the probability of a correct response to a dichotomous item "i", usually a multiple-choice question, is: where formula_1 indicates that the person abilities are modeled as a sample from a normal distribution for the purpose of estimating the item parameters. After the item parameters have been estimated, the abilities of individual person are estimated for reporting purposes. formula_4,