Hi

adkikani,

**Quote:**

the median of 17 means that 17 is the average of 12th and 13th greatest numbers of arrivals.

My understanding:

Median can be decimal or an integer for even number of elements in a sequence.

e.g. S1: {1,2,2,3}

Here, mean = (2+2)/ 2 = 2

S2: {1,2,3,4}

Mean = (2+3) / 2 = 2.5

Absolutely correct.

**Quote:**

In above quote, am I supposed to find mean of 12 and 13? How is it equal to 17?

What is said in the question:-

flights arrive at XYZ airport every hour for 24 hours. It means,

every hour corresponds to certain number of flights( minimum no of flights being 1).

We have 24 hours in a day. So, we have a minimum of 24*1=24 numbers of flights arriving at XYZ.

Maximum number of flights could be any number depending upon additional info provided in the question.

Question stem:- Is # of flights in 24 hrs>180 ?

St1:- On the same Saturday, the median number of flight arrivals every hour is 17.

We have total no of hours=24 ( If we consider it a set, then it has 24 data points and each data point has certain frequency(here no of flights))

Median number of flights is equal the mean number of flights at 12th and 13th hours or data point when the data points are arranged in ascending or descending fashion.

No of hours ---------------.

No of flights/frequency1st---------------------------- \(\geq1\)

2nd---------------------------- \(\geq1\)

.

.

.

11th---------------------------\(\geq1\)

12th--------------------------- \(\leq17\) & \(\geq1\)

Median-------------------------1713th---------------------------- \(\geq17\) & \(\leq33\)

.

.

.

24th--------------------------- \(\geq17\)

We can take the above data in descending order too.

Minimum # of flights arrived in 24 hrs=11*1+

17*1+17*1+11*17=11+

17+17+187=232>180

Sufficient.

P.S:-

You have to take the average of no of flights in 12th hour and no of flights in 13th hour. Not the average of 12 and 13. 12 and 13 represent the hour number not the no of flights in 12th and 13th hours respectively.Hope it helps.

_________________

Regards,

PKN

Rise above the storm, you will find the sunshine