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Chapter 4: Q AP1.13. (page 278)

The frequency table below summarizes the times

in the last month that patients at the emergency room of a

small-city hospital waited to receive medical attention.

Which of the following represents possible values for the median and mean waiting times for the emergency room last month?

(a) median = 27 minutes and mean = 24 minutes

(b) median = 28 minutes and mean = 30 minutes

(c) median = 31 minutes and mean = 35 minutes

(d) median = 35 minutes and mean = 39 minutes

(e) median = 45 minutes and mean = 46 minutes

Short Answer

Expert verified

The correct option is (b).

Step by step solution

01

Given information

The figure is :

Waiting timeFrequency
Less than 10 minutes5
At least 10 but less than 20 minutes24
At least 20 but less than 30 minutes
45
At least 30 but less than 40 minutes
38
At least 40 but less than 50 minutes
19
At least 50 but less than 60 minutes
7
At least 60 but less than 70 minutes
2
02

Concept

A simple random sample (SRS) of size n is made up of n people chosen from the population with an equal chance of being the sample that is actually chosen.

03

Calculation

The frequency table below highlights the times that patients in a small-city hospital's emergency room waited for medical attention in the previous month:

Class intervalxfc.f.f.x.
<10
55525
10-20152429360
20-302545741125
30-4035381121330
40-504519131855
50-60557138385
60-70652140130
Total
N=140
4210





Mean=鈭�i=1nfixi鈭�i=1nfi=4210140=30.071=30minutes

Median=l+h2(N2-c)=20+10451402-29=29.11=29minutes

Hence the correct option is (b).

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