In the clinic's waiting-time table, what is the…

In the clinic's waiting-time table, what is the frequency of the median class?

Question 31

MediumOriginal question

The table gives a 'less than' cumulative frequency distribution of the waiting times of 40 patients at a clinic.

In the clinic's waiting-time table, what is the frequency of the median class?

11Correct answerYour answer12Correct answerYour answer20Correct answerYour answer23Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer B

Correct answer: B

$n = 40$ , so $n \div 2 = 20$ . The first cumulative frequency to reach 20 is 23, for 'less than 30', so the median class is 20–30.
Its frequency is $23 - 11 = 12$ .

Worth noting

23 is the cumulative frequency, not the class's own frequency. 20 is $n \div 2$ , and 11 is the cumulative frequency before the median class.

Ten questions from Mean, Median and Mode, at your own pace.

Ten questions from Mean, Median and Mode, at your own pace.