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You are interested in how much time students spend on the Internet each day. Here are data on the time spent on the Internet (in minutes) for a particular day reported by a random sample of 30 students at a large high school:

(a) Construct a histogram of these data.

(b) Are there any outliers? Justify your answer.

(c) Would it be better to use the mean and standard deviation or the median and IQR to describe the center and spread of this distribution? Why?

Short Answer

Expert verified

Part (b) Outliner is: Min is 19max is 325, Median is 48, Q1 is 32, Q3 is 80

Part (c) The sample standard deviation is 75.57302930

Part (a)

Step by step solution

01

Part (a) Step 1: Given information

The figure is

7202425252828303235
42434445464748485051
7275777879838788135151
02

Part (a) Step 2: Concept

A histogram is a graphing tool that is often used. It's used to summarise data that's either discrete or continuous and measured on an interval scale. It's commonly used to demonstrate the key aspects of data distribution in a user-friendly manner.

03

Part (a) Step 3: Explanation

For the given data, the proper histogram is as above.

04

Part (b) Step 1: Explanation

It can be seen from the above histogram that,

1. The minimum: 19

2. (The median of the initial group is the lower or initial quartile) Q1:32

3. The median: 48

4. (The median of the second group is the upper or third quartile) Q3:80

5. The maximum: 325

05

Part (c) Step 1: Calculation

The mean of the given data isx=1n∑i=1nxi

n= a number of values.

xi,i=1,nare the values.

Where, If 30points are given in this case, then n=30

The sum of the point is,∑i=1nxi=2382

Thus, the meanx=1302382=3975=79.4

The sample standard variation of given data is, s=1n-1∑i=1n(xi−x)2

Where,

n= a number of values.

xi,i=1,nare the values.

x=mean of the values

The mean of data is,x=3975

As here in this example, 30points are given, then n=30

Sum of(xi−x)2∑i=1n(xi−x)2=828136/5(xi−x)2∑i=1n(xi−x)2=[1/(30−1)](828136/5)=(1/29)(828136/5)=828136/145

Finally, s=828136/145=230019930/145≈75.57302930

Thus, the sample standard deviation is75.57302930

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