资源描述
一、选择题：2*10=20分1、要了解400个学生的学习情况，则总体单位是( B ) 。 A 400个学生 B 每一个学生 C 400个学生的成绩 D 每一个学生的成绩2、只与一个自由度有关的是（ A ）A 分布 B 超几何分布 C 泊松分布 D F分布3、将总体按与研究有关的标志进行分组，然后再随机地从各组中抽选单位组成样本。这种抽样方式叫（ B ）。A 简单随机抽样 B 类型抽样 C 等距抽样 D 整群抽样。4、在方差分析中，自变量是（ A ）。A 定类变量 B 定序变量 C 定距变量 D 定比变量5、 某城市男性青年27岁结婚的人最多，该城市男性青年结婚平均年龄为26.2岁，则该城市男性青年结婚的年龄分布为（B）。 A正偏 B负偏 C对称 D不能作出结论6、分析统计资料，可能不存在的平均指标是（ A ）。A 众数 B 算术平均数 C 中位数 D 几何平均数7、在一个左偏的分布中，小于平均数的数据个数将（ C ）。A 超过一半 B 等于一半C 不到一半 D 视情况而定8、若P（A）0.2，（B）0.6，P（A/B）0.4，则（ D ）。A 0.8 B 0.08 C 0.12 D 0.24。9、关于学生t分布，下面哪种说法不正确（ B ）。A 要求随机样本 B 适用于任何形式的总体分布 C 可用于小样本 D 可用样本标准差S代替总体标准差10、对于大样本双侧检验，如果根据显著性水平查正态分布表得Z/2196，则当零假设被否定时，犯第一类错误的概率是( C )。A 20% B 10% C 5% D1% 二、判断题：2*10=20分 1、所有的统计指标都是变量。 （ 对 ）2、统计所研究的对象就是社会经济现象的数量方面。 （错 ）3、随机变量在相同的条件下进行观测，其可能实现的值不止一个。 （对 ）4、在社会现象中，即使相同的意识作用也完全可能有不确定的结果，这就提供了概率论应用的可能性。 （ 对 ）5、成功次数的期望值是决定泊松分布的关键因素。 （ 对 ）6、进行区间估计，置信水平总是预先给定的。 （ 对 ）7、可以对置信水平作如下解释：“总体参数落在置信区间的概率是（1-）”。（错 ）8、将收集到得的数据分组，组数越多，丧失的信息越多。 （错 ） 9、N个变量值连乘积的平方根，即为几何平均数。 （错 ） 10、当样本容量n无限增大时，样本均值与总体均值的绝对离差小于任意正数的概率趋于零。 （错 ） 三、简答题：5*7=35分 1、大数规律大数规律是随机现象出现的基本规律，它的一般意义是：观察过程中每次取得的结果可能不同（因为具有偶然性），但大量重复观察结果的平均值却几乎接近某个确定的数值。2、配对样本所谓配对样本，指只有一个总体，双样本是由于样本中的个体两两匹配成对而产生的。3、消减误差比例变量间的相关程度，可以用不知Y与X有关系时预测Y的误差，减去知道Y与X有关系时预测Y的误差，再将其化为比例来度量。将削减误差比例记为PRE。4、同分对如果在X序列中，我们观察到（此时Y序列中无），则这个配对仅是X方向而非Y方向的同分对；如果在Y序列中，我们观察到（此时X序列中无），则这个配对仅是Y方向而非X方向的同分对；我们观察到，也观察到，则称这个配对为X与Y同分对。5、什么是分层抽样？ 分层抽样也叫类型抽样，就是先将总体按某种特征或属性分若干类别或层次，再按照一定比例在各个子类别或层次中随机抽取，最后将各抽取的单位合并成样本。 6、简述回归分析和相关分析之间的密切联系。一般说来，只有当两个变量之间存在着较高程度的相关关系时，回归分析才变得有意义和有价值。相关程度越高，回归预测越准确。因此，往往先进行相关分析，然后才选用有明显相关关系的变量作回归分析。与此同时，相关关系往往要通过回归分析才能阐释清楚，例如皮尔逊相关系数的PRE性质。回归分析具有推理的性质，而相关分析从本质上讲只是对客观事物的一种描述，知其然而不知其所以然。因而从分析层次上讲，回归分析更深刻一些。7、P 值决策与统计量的比较P 值是被称为观察到的(或实测的)显著性水平。用P值进行检验比根据统计量检验提供更多的信息统计量检验是我们事先给出的一个显著性水平，以此为标准进行决策，无法知道实际的显著性水平究竟是多少四、计算分析题：15=分 1、一种以休闲和娱乐为主题的杂志，声称其读者群中有80%为女性。为验证这一说法是否属实，某研究部门抽取了由100人组成的一个随机样本，发现有46个女性经常阅读该杂志。取显著性水平 a=0.05，检验该杂志读者群中女性的比例是否为80%？H0 ：p = 80% H1 ：p 80% a = 0.05 n = 100检验统计量:结论: 没有证据表明“该杂志声称读者群中有80%为女性”的看法正确 2、有四个品牌的彩电在五个地区销售，为分析彩电的品牌(因素A)和销售地区(因素B)对销售量是否有影响，对每个品牌在各地区的销售量取得以下数据，见下表。试结合Excel输出的结果分析品牌和销售地区对彩电的销售量是否有显著影响？ 不同品牌的彩电在各地区的销售量数据 品牌(因素A) 销售地区( 因素B )B1B2B3B4B5A1A2A3A4365345358288 350368323280 343363353298 340330343260 323333308298 Excel输出的结果如下：1、对因素A提出的假设为H0: m1=m2=m3=m4 (品牌对销售量没有影响)H1: mi (i =1,2, , 4) 不全相等 (品牌对销售量有影响)2、对因素B提出的假设为H0: m1=m2=m3=m4=m5 (地区对销售量没有影响)H1: mj (j =1,2,5) 不全相等 (地区对销售量有影响)结论： FA18.10777Fa3.4903，拒绝原假设H0，说明彩电的品牌对销售量有显著影响FB2.100846 Fa3.2592，接受原假设H0，说明销售地区对彩电的销售量没有显著影响 已知：=0.10时，Z/2=1.65 =0.05时，Z/2=1.96 =0.01时，Z/2=2.58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.
展开阅读全文