文章目錄

• • • 什么是頻率？
    • 頻率該如何度量？
    • 相對頻率是如何表示的？
    • 參考資料

什么是頻率？

頻率是觀察到變量（數據項）的特定值發生的次數。

頻率該如何度量？

根據所需的目的，可以以不同的方式表示值的頻率。

絕對頻率描述了觀察到變量（數據項）的特定值發生的次數。表達頻率的最簡單方法是絕對值。

相對頻率描述了觀察到變量（數據項）的特定值相對于該變量的值的總數發生的次數。通過將絕對頻率除以變量的值的總數來計算相對頻率。

相對頻率是如何表示的？

Ratios, rates, proportions and percentages are different ways of expressing relative frequencies.

• A ratio compares the frequency of one value for a variable with another value for the variable.
  The first value identified in a ratio must be to the left of the colon “:” and the second value must be to the right of the colon (1st value : 2nd value).

  For example, in a total of 20 coin tosses where there are 12 heads and 8 tails, the ratio of heads to tails is 12:8. Alternatively, the ratio of tails to heads is 8:12.

• A rate is a measurement of one value for a variable in relation to another measured quantity.

  For example, in a total of 20 coin tosses where there are 12 heads and 8 tails, the rate is 12 heads per 20 coin tosses. Alternatively, the rate is 8 tails per 20 coin tosses.

• A proportion describes the share of one value for a variable in relation to a whole.
  It is calculated by dividing the number of times a particular value for a variable has been observed, by the total number of values in the population.

  For example, in a total of 20 coin tosses where there are 12 heads and 8 tails, the proportion of heads is 0.6 (12 divided by 20). Alternatively, the proportion of tails is 0.4 (8 divided by 20).

• A percentage expresses a value for a variable in relation to a whole population as a fraction of one hundred.
  The percentage total of an entire dataset should always add up to 100, as 100% represents the total, it is equal to the ‘whole’.
  A percentage is calculated by dividing the number of times a particular value for a variable has been observed, by the total number of observations in the population, then multiplying this number by 100.

  For example, in a total of 20 coin tosses where there are 12 heads and 8 tails, the percentage of heads is 60% (12 divided by 20, multiplied by 100). Alternatively, the percentage of tails is 40% (8 divided by 20, multiplied by 100).

參考資料

Describing Frequencies

總結

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