Excel在《生物统计学》F分布中的应用与探讨

本文主要介绍了Excel中的FDIST函数和FINV函数在F分布中的概率和临界值的计算,方便学生或其他人员利用Excel直接获得其概率或临界值,从F分布的概率计算上来看,Excel统计分析功能略胜于SAS和SPSS。     

煤与瓦斯突出危险敏感指标的确定

介绍用钻屑指标法预测煤巷掘进工作面突出危险性方法以及在前岭煤矿预测试验结果，确定了突出危险敏感指标及其临界值和突出危险性等级。     

分析临界条件解决动力学问题

所谓临界条件,就是当系统的运动形式、现象、性质或过程发生转变时,系统在转折的关键点所处的物理状态和物理条件。符合临界条件的物理量称为临界值,临界值是物理现象或物理过程转折的分界点,它所对应的临界条件往往隐蔽在变化过程中,需要仔细分析、挖掘。1在“相对静止”与“相对滑动”转化过程中分析临界条件。例1如图,A、B两物块的质量分别为10kg,4kg,A、B之间能产生的最大静摩擦力为20N,A放在光滑的水平地面上,现用水平力F1拉A物,或改用水平力F2拉B物,均要使A、B无相对滑动,求F1F2的最大值。     

分解力的两种方法（高一）

题一个力F=10N,分解成两个分力F1和F2,已知F1的方向与F成30°角,而分力F2的大小为6N.求: (1)分力F1的大小为多少? (2)分力F2的方向如何? 解法1三角形法则 合力与其分力可以构成一个矢量三角形,利用边角关系,可以分析各分力的变化情况. 从图1可知,当分力F1由零逐渐增加时,分力F2先减少后增加,显然当分力F2与分力F1相互垂直时,分力F2为最小值.即F2|min=Fsinθ. 以这个最小值为临界值,对题目进行分析,有如下三种情况:     

Plackett-Burman饱和设计下数据分析方法的标准化研究

为了比较Plackett-Burman饱和设计下10种数据分析方法的优劣,以试验错误率为标准进行标准化,通过SAS/IML语言模拟出各种方法在P-B设计下的临界值,并以势为评价标准,提出12次Plackett-Burman设计下的比较研究结论.     

临界值法与必要条件

文章论述了临界值法与必要条件的关系,探究临界值法结合必要条件求解不等式恒成立问题,即在使用临界值法的过程中,先利用方程的部分解以及临界点产生必要条件,再证明其充分性.解决了方程不能解、函数不是关于参数单调的情况下临界值法的使用问题,是对临界值法的进一步完善.     

从女子标枪成绩的多元回归分析中看样本含量与F 的取值对结论的影响

以女子标枪6 个变量因素为例, 对三组不同样本含量和F 的取值进行了多元回归分析, 结果表明: 在样本的成绩范围内, 样本n = 10 建立的“最优”回归方程与样本n = 60 , n = 30 的结论基本相同. 认为用样本n = 10建立“最优”回归方程既方便又省力. 强调在作逐步回归分析时, F 的检验临界值要取低些, 并指出: 在指标因素过多时, 应先聚类, 然后分别选出影响最大的指标建立“最优”方程.     

从女子标枪成绩的多元回归分析中看样本含量与F的取值对结论的影响

以女子标枪6个变量因素为例，对三组不同样本含量和F的取值进行了多元回归分析，结果表明，在样本的成绩范围内，样本n=10建立的“最优”回归方程与样本n=60,n=30的结论基本相同，认为用样本n=10建立“最优”回归方程既方便又省力，强调在作逐步回归分析时，F的检验临界值要取低些，并指出：在指标因素过多时，应先聚类，然后分别选出影响最大的指标建立“最优”方程。     

刚体稳定平衡条件的变分求法

本文用变分的方法求解刚体稳定平衡的条件——临界值,给出了两种基本方法,并举例说明其应用。     

浅谈力学临界值

中学物理中，临界值是广泛存在而又十分重要的问题．本文拟在力学范围内，将有关临界值问题作一归类，举例阐析其确定方法和意义．     

酮洛芬骨架缓释片相对生物利用度研究

采用高效液相色谱法,以布洛芬为内标,对24 h酮洛芬骨架缓释片试验制剂以24名健康志愿者进行多剂量人体相对生物利用度试验.结果表明,试验制剂具有明显的缓释药动学特征,参比制剂的Cmax显著高于试验制剂（p〈0.01）,试验制剂给药后的tmax延迟,且吸收程度与作为标准参比制剂的市售缓释片相比无显著差异,人体相对生物利用度为103.76%.经统计学检验表明这两种制剂具有生物等效性,试验制剂具有峰谷浓度差异小、波动幅度小的特点,显示出缓释特征.     

Flipping Online Analytics Classes: Achieving Parity with Their Face‐To‐Face Counterparts

We show how the principles of flipped learning that have been successfully applied to analytics classes taught face‐to‐face (F2F) at the undergraduate and graduate levels were emulated in corresponding online classes. Student satisfaction in the online flipped analytics classes was compared to student satisfaction in the F2F flipped analytics classes. Data were collected between the Spring 2016 and Fall 2018 semesters and involved two instructors with a sample of 726 students. The results of an independent samples t‐test showed that there was no significant difference in satisfaction between the online and F2F offerings. A binary logistics regression analysis on the data revealed that whether the flipped course was taught F2F or online had no significant effect on students recommending the course to their peers. The results suggest that flipped learning is transferrable to online analytics courses and yields student satisfaction at par with equivalent F2F flipped courses.     

Comparing the Impacts of a Problem-Based Computer-Assisted Instruction and the Direct-Interactive Teaching Method on Student Science Achievement

This study explored the effects of a Problem-Based Computer-Assisted Instruction (PBCAI) on students' earth science achievement in Taiwan. One hundred and fifty-nine 10th grade students enrolled in four sections of a mandatory earth science course participated in this pretest–posttest control-group experiment. During a 2-week period, the experimental group students (n = 84) received the PBCAI while the comparison group students (n = 75) received a Direct-Interactive Teaching Method (DITM) accompanying with regular computer-internet usage. An analysis of covariance on the Earth Science Achievement Test posttest scores with students' IQ and pretest scores as the covariates suggested that (a) the PBCAI was more effective in promoting students' achievement than was the DITM (F = 4.91, p < .028), and that (b) students in the experimental group had significantly higher achievement scores than did students in the comparison group, especially on the knowledge (F = 7.74, p < .017) and comprehension (F = 5.73, p < .017) test items, but not on the application (F = .07, p > .017) test items.     

大学生课桌文化的心理现状研究

运用开放式问卷和内容分析法对课桌文化进行分析,以此探究大学生的心理现状。结果表明:大学生课桌文化体现在八种心理类型:思索人生的意义型(F1)、情爱探索与困惑型(F2)、自我迷茫型(F3)、对性的看法型(F4)、对学校的不满型(F5)、评价他人与自我型(F6)、无聊宣泄型(F7)、学习与考试焦虑型(F8)。各种心理类型的差异非常显著,其中F1、F2、F7和F8体现明显。此外,除无聊宣泄型外,其他类型的心理特征的差异显著;一般与考研教室的课桌文化的心理类型差异非常显著。     

硅酸盐细菌几种功能的研究

介绍了对硅酸盐细菌分解钾矿石能力的研究，并对硅酸盐细菌的促生作用和抑菌作用进行了初步探讨。指出：硅酸盐细菌无分解钾长石的能力；在含菌10^5-10^7个／mL的范围内能使萌芽不高的陈旧小麦种子萌发率提高2－3倍；盆栽试验表明在灭菌土壤里接种硅酸盐细菌比不接种能显增加苗期植物的生长量；平板试验表明硅酸盐细菌对棉枯萎病、小麦全蚀病、小麦赤霉病等植物病原菌有明显抑制作用。     

Effects of Practical Constraints on Item Selection Rules at the Early Stages of Computerized Adaptive Testing

The purpose of this study was to compare the effects of four item selection rules—(1) Fisher information (F), (2) Fisher information with a posterior distribution (FP), (3) Kullback-Leibler information with a posterior distribution (KP), and (4) completely randomized item selection (RN)—with respect to the precision of trait estimation and the extent of item usage at the early stages of computerized adaptive testing. The comparison of the four item selection rules was carried out under three conditions: (1) using only the item information function as the item selection criterion; (2) using both the item information function and content balancing; and (3) using the item information function, content balancing, and item exposure control. When test length was less than 10 items, FP and KP tended to outperform F at extreme trait levels in Condition 1. However, in more realistic settings, it could not be concluded that FP and KP outperformed F, especially when item exposure control was imposed. When test length was greater than 10 items, the three nonrandom item selection procedures performed similarly no matter what the condition was, while F had slightly higher item usage.     

The Robustness of the Analysis of Variance and the Tukey WSD Test under Various Patterns of Heterogeneous Variances

The WSD and F tests show the same response when the homogeneous variance assumption is violated. Both are robust when the ns are equal, but may be either seriously conservatively biased or seriously permissively biased when heterogeneous variances are combined with unequal ns. The use of equal ns is recommended for either test. There is no virtue in insisting that the F test be significant prior to conducting the WSD when the alternative to the null is μ_i ≠ μ_j. However, the conservative bias created by this procedure is small when K = 4; as is the permissive bias created by conducting both tests. For uniformly distributed μ’s, the two tests have very similar powers. This condition would not be expected for different arrangements of the μ’s.     

590MPa级大梁钢的奥氏体连续冷却转变动力学研究

通过Formastor-F全自动相变记录仪上测定了铌钛复合强化型590MPa级大梁钢在不同冷速下的奥氏体转变动力学曲线,并结合金相组织和硬度测试,分析了不同冷却速度对组织转变、晶粒尺寸和硬度的影响规律。在不同的冷却范围内,试验钢分别获得铁素体、珠光体、贝氏体和马氏体。当冷速在0.5℃/s以下时,获得F+P,在1℃/s~10℃/s之间时,获得F+P+B,在15℃/s~50℃/s之间时,获得F+B,在100℃/s时,获得B+M。试验结果为轧钢生产提供了工艺指导依据。     

Directed forgetting in pigeons: Analysis of cue functions

In delayed matching-to-sample with pigeons, brief postsample cues signaled different trial outcomes. The normal comparison stimuli followed the cue to remember (R cue). In the comparison-omission procedure, comparison stimuli and reinforcement were omitted following the cue to forget (F cue). In the comparison-substitution procedure, comparison stimuli were replaced by a single stimulus and reinforcement for a single response following the F cue. Infrequent probe trials revealed that F cues disrupted matching, with the amount of accuracy loss dependent on the length of the cue-comparison delay. These results, however, were found only with the comparison-omission procedure (Experiment 1). Replacing the comparison stimuli with another simultaneous (unconditional) discrimination revealed no accuracy loss in F-cue probes (Experiment 2), even though choice latencies were again lengthened by F cues. These results suggest that, while the F cue interferes with performance at the time of a retention test by slowing choices, it also interferes with sample retention. Alternative models of the cuing effect and its apparent dependence on end-of-trial reward are outlined.     

基于TMS320F2812的CANopen协议的通信实现

CANopen是一种开放的现场总线协议,是欧洲嵌入式工业控制网络的主要标准协议.在分析CANopen协议的对象字典、设备模型和通信对象等的基础上,采用CANopen协议的子协议DS301实现了基于CAN总线的TMS320F2812与主控模拟调试软件之间的通讯,并通过测试验证了通讯过程中信息传递的正确性和可靠性.