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电大社会统计学复习材料小抄简答题1、统计数据的质量要求：1、精度：最低的抽样误差或随机误差； 2、准确性：最小的非抽样误差或偏差；3、关联性：满足用户决策、管理和研究的需要；4、及时性：在最短的时间里取得并公布数据；5、一 致 性：保持时间序列的可比性； 6、最低成本：以最经济的方式取得数据。2、抽样误差及其影响因素：1、由于抽样的随机性所带来的误差； 2、所有样本可能的结果与总体真值之间的平均性差异； 3、影响抽样误差的大小的因素：样本量的大小，总体的变异性。3、判断计量优劣的评判标准：用样本的估计量直接作为总体参数的估计值，无偏性：估计量抽样分布的数学期望等于被估计的总体参数 ；有效性：对同一总体参数的两个无偏点估计量，有更小标准差的估计量更有效； 一致性：随着样本容量的增大，估计量的值越来越接近被估计的总体参数。4、假设检验的一般步骤：（1）陈述原假设和备择假设；（2）从所研究的总体中抽出一个随机样本；（3）确定一个适当的检验统计量，并利用样本数据算出其具体数值；（4）确定一个适当的显著性水平，并计算出其临界值，指定拒绝域；（5）将统计量的值与临界值进行比较，作出决策；（6）统计量的值落在拒绝域，拒绝H0，否则不拒绝H0。5、假设检验中的两类错误及其之间的关系错误：1、第类错误(弃真错误)原假设为真时拒绝原假设，第类错误的概率记为a，即显著性水平；2、第类错误(取伪错误)原假设为假时未拒绝原假设,第类错误的概率记为b。a和b的关系就像翘翘板，a小b就大，a大b就小。因此，在样本容量n固定情况下，不能同时减少两类错误!一般采用增加样本容量的办法来解决。关系：当显著性水平a减小时，由于拒绝域的减小，弃真的错误会减小，但由此而来的是接受域增大了，因此纳伪的概率b要增大。反之亦然（P235）。也就是说如果要减小b，就增大显著性水平a。6、置信区间与置信度的关系表达式：称作置信区间。称作置信度，可信度，或置信水平。称置信水平。在样本容量一定的情况下，置信区间和置信度是相互制约的。置信度愈大，则相应的置信区间也域宽。当把区间估计得小一些，估计的精确程度提高了，但换取的代价将是估错的可能性增加了，也就是可靠性或置信度下降了。（P201）7、正态分布曲线的特征：（）一个高峰：曲线是单峰，有一个最高点。（）一个对称轴。曲线的高峰处有一个对称轴，在轴的左右两边是对称的。（）一个渐近线。曲线无论向左或向右延伸，都愈来愈接近横轴，但不会和横轴相交，以横轴为渐近线。4.正态分布一般用表示。(P139)8、方差分析的基本假定：（二）e的分布为正态分布要求每一个Ai所对应yi的分布都呈正态。总结起来，进行方差分析，要求总体中每一个自变量的取值对应的因变量yi满足正态分布9、方差分析的基本原理和逻辑：基本原理：变异的可加性。根据这一原理，将数据的总变异分解为不同来源的变异（组间、组内），根据不同来源的变异在总变异中所占的比重对造成数据变异的原因作出解释。10、非参数检验的优缺点：优点：没有严格的前提假设，对总体分布无需加以限制，计算量也比较少。缺点：在同等情况下，检验的效率较差。未能充分利用资料的全部信息，目前还不能处理交互作用。（整理人：燕梅 我会整理小组工作，其他科目有同学整理的请大家一起分享下哈这样大家备考都会更有效）。其他知识点u 随机现象：事先无法确定会出现那种结果的现象总体：所研究的全部元素的集合，其中的每一个元素称为个体，分为有限总体和无限总体。样本：从总体中抽取的一部分元素的集合，构成样本的元素的数目称为样本容量。参数：研究者想要了解的总体的某种特征值。统计量：根据样本数据计算出来的一个量。u 变量：说明现象某种特征的概念。分类变量：说明事物类别的一个名称。顺序变量：说明事物有序类别的一个名称。数值型变量：说明事物数字特征的一个名称。离散变量：取有限个值； 连续变量：可以去无穷多个值。u 普查：为特定目的专门组织的非经常性全面调查。典型调查：从调查对象的全部单位中选择少数典型单位进行调查。重点调查：从调查对象的全部单位中选择少数重点单位进行调查。u 数据质量的要求误差：测量值与真实值之间的差异。随机误差：在同一条件下，对同一量值进行多次测量时，其数值和符号以不可预见的方式而变化的那部分误差。系统误差：在一定的测量条件下，对同一被测物进行多次重复测量时，误差值的大小和符号保持不变，或者在条件变化时，按一定规律变化的误差。抽样误差：由于抽样的随机性所带来的误差。非抽样误差：除抽样误差之外的，由于其他原因造成的样本观察结果与总体真值之间的差异。u 分类数据的整理（指标）与图形频数：落在各类别中的数据个数。比例：某一类别数据占全部数据的比值，可以比较不同样本。百分比：将对比的基数作为100而计算的比值。比率：把计算比例时所用的基数变大，如100、1000、10000等，最常用的是百分比率。对比值：不同类别数值的比值。顺序数据的整理与显示：累积频数、累积频率数值型数据的整理 组限统计表设计的要求：3W要求 which when what 、集中趋势测量及计算、三者的比较及应用。u 离散程度的测量及运用计算：题1：甲乙两同学分别来自一年级某班和二年级某班，某次期末考试，两同学均考了80分，一班的平均分为80分，标准差为10，二班的平均分为70分，标准差为10，这两个同学在班级上的成绩是否一样？题2：政治物理甲7060乙6070政治平均分为70，标准差为10，物理平均分为50，标准差为10。甲乙两人的总成绩是否相同？u 标准正态分布（表）的应用:（见P151）u 抽样调查的方法：简单随机抽样，分为重复抽样、不重复抽样；等距抽样（机械抽样、系统抽样）；分层抽样（类型抽样、分类抽样），根据各层抽取比例是否相等，可分作定比抽样和异比抽样。u 抽样误差：即指样本估计值与总体参数之间的差异，例如样本平均值X与总体均值u之差。u 参数估计:(见PPT)u 回归、相关与假设检验：（见P333或PPT）u 方差分析：是分析或检验总体间的均值是否有所不同，而不是方差是否有所不同，但其 检验所用的方法或手段则是通过方差来进行的。方差分析分一元方差分析、二元方差分析以及多元方差分析。u 非参数检验（P416）：就是指“对分布类型已知总体、进行参数检验”之外，所有检验方法的总称。 优点：对总体分布无须加以限制，计算量也比较少，简单易行； 缺点：检验的效率较差（费参数检验法一般要比用相应的参数检验需要较大的样本）。请您删除一下内容，O(_)O谢谢！2016年中央电大期末复习考试小抄大全，电大期末考试必备小抄，电大考试必过小抄Acetylcholine is a neurotransmitter released from nerve endings (terminals) in both the peripheral and the central nervous systems. It is synthesized within the nerve terminal from choline, taken up from the tissue fluid into the nerve ending by a specialized transport mechanism. The enzyme necessary for this synthesis is formed in the nerve cell body and passes down the axon to its end, carried in the axoplasmic flow, the slow movement of intracellular substance (cytoplasm). Acetylcholine is stored in the nerve terminal, sequestered in small vesicles awaiting release. When a nerve action potential reaches and invades the nerve terminal, a shower of acetylcholine vesicles is released into the junction (synapse) between the nerve terminal and the effector cell which the nerve activates. This may be another nerve cell or a muscle or gland cell. Thus electrical signals are converted to chemical signals, allowing messages to be passed between nerve cells or between nerve cells and non-nerve cells. This process is termed chemical neurotransmission and was first demonstrated, for nerves to the heart, by the German pharmacologist Loewi in 1921. Chemical transmission involving acetylcholine is known as cholinergic. Acetylcholine acts as a transmitter between motor nerves and the fibres of skeletal muscle at all neuromuscular junctions. At this type of synapse, the nerve terminal is closely apposed to the cell membrane of a muscle fibre at the so-called motor end plate. On release, acetylcholine acts almost instantly, to cause a sequence of chemical and physical events (starting with depolarization of the motor endplate) which cause contraction of the muscle fibre. This is exactly what is required for voluntary muscles in which a rapid response to a command is required. The action of acetylcholine is terminated rapidly, in around 10 milliseconds; an enzyme (cholinesterase) breaks the transmitter down into choline and an acetate ion. The choline is then available for re-uptake into the nerve terminal. These same principles apply to cholinergic transmission at sites other than neuromuscular junctions, although the structure of the synapses differs. In the autonomic nervous system these include nerve-to-nerve synapses at the relay stations (ganglia) in both the sympathetic and the parasympathetic divisions, and the endings of parasympathetic nerve fibres on non-voluntary (smooth) muscle, the heart, and glandular cells; in response to activation of this nerve supply, smooth muscle contracts (notably in the gut), the frequency of heart beat is slowed, and glands secrete. Acetylcholine is also an important transmitter at many sites in the brain at nerve-to-nerve synapses. To understand how acetylcholine brings about a variety of effects in different cells it is necessary to understand membrane receptors. In post-synaptic membranes (those of the cells on which the nerve fibres terminate) there are many different sorts of receptors and some are receptors for acetylcholine. These are protein molecules that react specifically with acetylcholine in a reversible fashion. It is the complex of receptor combined with acetylcholine which brings about a biophysical reaction, resulting in the response from the receptive cell. Two major types of acetylcholine receptors exist in the membranes of cells. The type in skeletal muscle is known as nicotinic; in glands, smooth muscle, and the heart they are muscarinic; and there are some of each type in the brain. These terms are used because nicotine mimics the action of acetylcholine at nicotinic receptors, whereas muscarine, an alkaloid from the mushroom Amanita muscaria, mimics the action of acetylcholine at the muscarinic receptors. Acetylcholine is the neurotransmitter produced by neurons referred to as cholinergic neurons. In the peripheral nervous system acetylcholine plays a role in skeletal muscle movement, as well as in the regulation of smooth muscle and cardiac muscle. In the central nervous system acetylcholine is believed to be involved in learning, memory, and mood. Acetylcholine is synthesized from choline and acetyl coenzyme A through the action of the enzyme choline acetyltransferase and becomes packaged into membrane-boundvesicles. After the arrival of a nerve signal at the termination of an axon, the vesicles fuse with the cell membrane, causing the release of acetylcholine into thesynaptic cleft. For the nerve signal to continue, acetylcholine must diffuse to another nearby neuron or muscle cell, where it will bind and activate areceptorprotein. There are two main types of cholinergic receptors, nicotinic and muscarinic. Nicotinic receptors are located at synapses between two neurons and at synapses between neurons and skeletal muscle cells. Upon activation a nicotinic receptor acts as a channel for the movement of ions into and out of the neuron, directly resulting indepolarizationof the neuron. Muscarinic receptors, located at the synapses of nerves with smooth or cardiac muscle, trigger a chain of chemical events referred to as signal transduction. For a cholinergic neuron to receive another impulse, acetylcholine must be released from the receptor to which it has bound. This will only happen if the concentration of acetylcholine in the synaptic cleft is very low. Low synaptic concentrations of acetylcholine can be maintained via a hydrolysis reaction catalyzed by the enzyme acetylcholinesterase. This enzyme hydrolyzes acetylcholine into acetic acid and choline. If acetylcholinesterase activity is inhibited, the synaptic concentration of acetylcholine will remain higher than normal. If this inhibition is irreversible, as in the case of exposure to many nerve gases and some pesticides, sweating, bronchial constriction, convulsions, paralysis, and possibly death can occur. Although irreversible inhibition is dangerous, beneficial effects may be derived from transient (reversible) inhibition. Drugs that inhibit acetylcholinesterase in a reversible manner have been shown to improve memory in some people with Alzheimers disease. abstract expressionism, movement of abstract painting that emerged in New York City during the mid-1940s and attained singular prominence in American art in the following decade; also called action painting and the New York school. It was the first important school in American painting to declare its independence from European styles and to influence the development of art abroad. Arshile Gorky first gave impetus to the movement. His paintings, derived at first from the art of Picasso, Mir, and surrealism, became more personally expressive. Jackson Pollocks turbulent yet elegant abstract paintings, which were created by spattering paint on huge canvases placed on the floor, brought abstract expressionism before a hostile public. Willem de Koonings first one-man show in 1948 established him as a highly influential artist. His intensely complicated abstract paintings of the 1940s were followed by images of Woman, grotesque versions of buxom womanhood, which were virtually unparalleled in the sustained savagery of their execution. Painters such as Philip Guston and Franz Kline turned to the abstract late in the 1940s and soon developed strikingly original stylesthe former, lyrical and evocative, the latter, forceful and boldly dramatic. Other important artists involved with the movement included Hans Hofmann, Robert Motherwell, and Mark Rothko; among other major abstract expressionists were such painters as Clyfford Still, Theodoros Stamos, Adolph Gottlieb, Helen Frankenthaler, Lee Krasner, and Esteban Vicente. Abstract expressionism presented a broad range of stylistic diversity within its largely, though not exclusively, nonrepresentational framework. For example, the expressive violence and activity in paintings by de Kooning or Pollock marked the opposite end of the pole from the simple, quiescent images of Mark Rothko. Basic to most abstract expressionist painting were the attention paid to surface qualities, i.e., qualities of brushstroke and texture; the use of huge canvases; the adoption of an approach to space in which all parts of the canvas played an equally vital role in the total work; the harnessing of accidents that occurred during the process of painting; the glorification of the act of painting itself as a means of visual communication; and the attempt to transfer pure emotion directly onto the canvas. The movement had an inestimable influence on the many varieties of work that followed it, especially in the way its proponents used color and materials. Its essential energy transmitted an enduring excitement to the American art scene.
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