十九世纪末,已经分离得到了许多引起传染病的细菌,但对一些传染病如口蹄疫、烟 草花叶病等却一直无法获得其病原细菌。1892年俄国学者伊万诺夫斯基(Ⅵ B a B KHⅱ)首次发现烟草花叶病的感染因子可以通过细菌滤器。1898年荷兰生物学家贝哲林 克(M.W. Beijerinck)进一步肯定了伊万诺夫斯基的结果,并将这类感染因子称为病毒 ( Virus)
Lecture 5 a distribution is a collection of scores order from lowest to highest value on the horizontal (X)axis, and in terms of T-Test frequency on the vertical (Y) axis. A ormal distribution sometimes referred to as a bell curve has a distribution that forms the shape of a bell. All you need to know to plot the normal distribution is the mean and standard deviation of the data This lecture covers