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Nutrition education in U.S. medical schools: latest update of a national survey

Purpose: To quantify the number of required hours of nutrition education at U.S. medical schools and the types of courses in which the instruction was offered, and to compare these results with results from previous surveys.

Method: The authors distributed to all 127 accredited U.S. medical schools (that were matriculating students at the time of this study) a two-page online survey devised by the Nutrition in Medicine Project at the University of North Carolina at Chapel Hill. From August 2008 through July 2009, the authors asked their contacts, most of whom were nutrition educators, to report the nutrition contact hours that were required for their medical students and whether those actual hours of nutrition education occurred in a designated nutrition course, within another course, or during clinical rotations.

Results: Respondents from 109 (86%) of the targeted medical schools completed some part of the survey. Most schools (103/109) required some form of nutrition education. Of the 105 schools answering questions about courses 最低25美元开户 and contact hours, only 26 (25%) required a dedicated nutrition course; in 2004, 32 (30%) of 106 schools did. Overall, medical students received 19.6 contact hours of nutrition instruction during their medical school careers (range: 0-70 hours); the average in 2004 was 22.3 hours. Only 28 (27%) of the 105 schools met the minimum 25 required hours set by the National Academy of Sciences; in 2004, 40 (38%) of 104 schools did so.

Conclusions:最低25美元开户 The amount of nutrition education that medical students receive continues to be inadequate.

Figures

Distribution of the total hours…

Distribution of the total hours of required nutrition instruction at U.S. medical schools.…

Distribution of the total hours of required nutrition instruction at U.S. medical schools. Representatives from 109 U.S. medical schools responded to the 2008–2009 Nutrition in Medicine survey (105 schools provided data in response to this question; 4 schools did not). The graph compares the number of schools meeting the recommended minimum of 25 hours of required nutrition education (white bars) with the number of schools providing less than the minimum number of required hours (black bars). The number of schools at each level of required nutrition instruction is indicated above each bar.

Distribution of the required nutrition…

Distribution of the required nutrition contact hours (i.e., the actual number of hours…

Distribution of the required 最低25美元开户 nutrition contact hours (i.e., the actual 最低25美元开户 number of hours of nutrition education) among the various types of medical school courses. Representatives from 109 U.S. medical schools responded to the 2008–2009 Nutrition in Medicine survey (100 schools provided data in response to this question; 9 schools did not). The 最低25美元开户 chart shows the distribution of required nutrition instruction throughout medical school curricula, whether in a designated nutrition course (20%) or integrated into other courses or learning environments (80%).

最低样本量的问题?

张戎:样本量与置信区间

在现实生活中,如何从一份海量的数据中选择合适的样本数量进行调研反馈,从而反映总体的情况是一个常见的问题。例如,在千万人口的城市进行某项调研如何选择样本;在某些国家的大选活动中,该发放多少问卷才能够反映整体情况;在机器学习模型的精确率抽检过程中,究竟应该选择多少样本数进行抽检,才能够反馈其模型的精确率;这些都是生活和工作中常遇到的问题。
通常来说,在这里会有两种比较常见的情况:
1. 通过置信度(confidence level),置信区间(confidence interval),总体数量(population),来计算样本数(sample size);
2. 通过置信度(confidence level),总体数量(population),样本数量(sample size),比例(percentage),来计算置信区间(confidence interval);
样本数的计算
当一个调研是随机抽样的时候,可以通过统计的方法来确定最小的样本数。一般情况下,样本数可以按照以下简单规则来进行选取:

  • 最小样本数是 100:对于一份抽样数据而言,至少要抽取 100 个样本来进行评估;而当全体总数小于 100 的时候,只需要全部抽取出来进行调研和分析即可;
  • 一个合适的最大样本数(maximum sample 最低25美元开户 size)可以用以下公式简单计算: \min(1000, 0.1 * N), 其中 N 表示总量;例如,当 N = 5000 时,最大样本数可以选择 500;而当 N = 200000 时,最大样本数只需要选择 1000 即可;
  • 在调研和抽样的时候,可以在最小样本数和最大样本数之间选择一个合适的值;
    (1)选择一个靠近最小样本数的值是因为:有限的资金和时间;只需要一个粗糙的估计;不需要对总体做类别分析且只需要一个整体的结论即可;大家对这个结论并不会有过多的质疑;这个分析结果并不会过多影响下游的分析决策。
    (2)选择一个靠近最大样本数的值是因为:充足的资金和时间;想要得到发一个精确的估计;有可能会对总体进行分组分析;大家会对这个结论有质疑;这个分析结果会导致下游的很多重要决策。
  • 对于样本数的选择,可以简单的参考下表:

通过以上的案例可以看出,在设置了置信度(Confidence Level),置信区间(Confidence Interval),总量(Population)之后,就可以得到一个样本数量(Sample Size Needed)。其中,置信区间也就是误差范围(Margin of 最低25美元开户 Error)。
例如,如果置信度是 95%,置信区间(confidence interval)= 4,在样本中有 47% 的比例选择了某个选项,那么就表示 95% 的置信度,在所有数据中有(47%-4%, 47%+4%)=(43%,51%) 的比例选择了某个选项。95% 置信度表示这句话正确的概率是 95%,99% 置信度表示这句话正确的概率是 99%。

置信区间的计算
置信区间的计算是由三个因素决定的,分别是:置信度(Confidence Level),样本数量(Sample Size),总量(Population)。一般来说,

统计理论分析
假设 N 表示总体的数量, X 表示总体中满足某个选项的数量, n 表示抽样的数量, x 表示样本中满足某个选项的数量。令 P=X/N, \hat

=x/n.
定理. 一个总体满足某个选项的比例可以通过样本中满足某个选项的比例来进行估计。如果置信度是 C ,且正态分布的概率用 Prob 表示,那么
Prob\bigg(-z^<\frac<\hat

-P><\sqrt<\frac<\hat

(1-\hat

)>>>换言之, \hat

-z^\sqrt<\frac<\hat

(1-\hat

)>>+\sqrt<\frac<\hat

(1-\hat

)>> . 其中 z^ 和 C 的关系如下图所示。其置信区间是 w = z^\sqrt<\frac<\hat

(1-\hat

)>>.

正态分布

長野県の最低賃金(一覧)

なお、地域別と特定(産業別)の両方の最低賃金が同時に適用される場合には、高い方の最低賃金の適用が優先されます。
⇒ 【最低賃金法第6条】労働者が2以上の最低賃金の適用を受ける場合は・・(中略)・・ 最高のものにより・・・(以下略)
ただし、特定(産業別)最低賃金については、当該産業に特有又は主要な業務に従事する「基幹的労働者」に対して適用されるため、それ以外の労働者には適用されず、地域別最低賃金が適用されます。
各特定(産業別)最低賃金の適用除外業務については、上記の表の特定(産業別)最低賃金件名のリンク先をご覧下さい。

Minimum Wage

workers

Track your regular work hours, break time, and overtime hours.

Overview

The federal minimum wage provisions are contained in the Fair Labor Standards Act (FLSA). The federal minimum wage is $7.25 per hour effective July 24, 2009. Many states also have minimum wage laws. Some state laws provide greater employee protections; employers must comply with both.

The FLSA does not provide wage payment collection procedures for an employee’s usual or promised wages or commissions in excess of those required by the FLSA. However, some states do have laws under which such claims (sometimes including fringe benefits) may be filed.