A dot plot is a visual representation of a data set. A horizontal axis shows the possible values of the data, and each data point is represented by a dot above its corresponding value on a horizontal axis.
Consider the following frequency table, which details the number of hours students in a class spent studying for a final exam:
| Hours Studied | Frequency |
|---|---|
To make a dot plot, we let a horizontal axis represent the number of hours studied. Then, we plot each data point as a dot above its corresponding value on the horizontal axis. The resulting plot is as follows:
The advantage of using dot plots is that their shape gives us an overall sense of how the data is distributed. For example, we can see immediately that most students spend at least two hours studying for the exam.
We can also create dot plots from data given as a list. Let's see an example.
Draw a dot plot that represents the data set shown below.
First, notice that we have three values in our data:
and
Next, we draw a number line from the smallest to the greatest value:
The data tells us the following:
The number appears three times. So, there will be dots over on the number line.
The number appears four times. So, there will be dots over on the number line.
The number appears once. So, there will be dot over on the number line.
Therefore, we get the dot plot shown below.
The frequency table below gives the time spent exercising in a small group of people over the past week.
| Hours Exercised | Frequency |
|---|---|
| $4$ | $2$ |
| $5$ | $4$ |
| $6$ | $4$ |
| $7$ | $5$ |
| $8$ | $3$ |
What dot plot represents the same data set?
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a
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b
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c
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d
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e
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What dot plot represents the data set shown below? \[ 8, \: 3, \: 2, \: 5, \: 8, \: 5, \: 8 \]
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a
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b
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c
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d
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e
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The dot plot below gives the distance (to the nearest kilometer) ran by a group of joggers one day. Each dot represents a single jogger.
The frequency table below represents the same information. What number is missing from the table?
| Distance (in kilometers) | Number of Joggers |
|---|---|
Notice the rd column of the dot plot. It tells us that there is jogger who ran kilometers.
Therefore, the missing value is
| Distance (in kilometers) | Number of Joggers |
|---|---|
The dot plot above gives the distances (rounded to the nearest ten kilometers) between some hotels and Los Angeles airport. Each dot represents a single hotel.
The frequency table below represents the same information. What number is missing from the table?
| Distance (in kilometers) | Number of Hotels |
|---|---|
| $10$ | $1$ |
| $20$ | $5$ |
| $30$ | $\fbox{$\,\phantom{0}\,$}$ |
| $40$ | $2$ |
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a
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$1$ |
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b
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$5$ |
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c
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$2$ |
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d
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$4$ |
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e
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$3$ |
The dot plot above gives the number of pairs of shoes bought by a group of customers in a small shoe store. Each dot represents a single customer.
The frequency table below represents the same information. What number is missing from the table?
| Number of Pairs of Shoes | Frequency |
|---|---|
| $1$ | $4$ |
| $2$ | $4$ |
| $3$ | $2$ |
| $4$ | $\fbox{$\,\phantom{0}\,$}$ |
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a
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$4$ |
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b
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$2$ |
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c
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$3$ |
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d
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$1$ |
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e
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$6$ |
What is the most common value in the data set represented by the dot plot below?
The plot tells us the following:
the value appears three times (there are dots over )
the value appears twice (there are dots over )
the value appears four times (there are dots over )
the value appears zero times (there are no dots over )
the value appears five times (there are dots over )
the value appears twice (there are dots over )
Therefore, the most common value among the given data set is
The dot plot above shows the ages of the players in a school soccer team. If each dot represents a player, how many players are in the team?
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a
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$4$ |
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b
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$12$ |
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c
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$50$ |
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d
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$8$ |
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e
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$14$ |
What is the most common value in the data set represented by the dot plot above?
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a
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$40$ |
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b
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$50$ |
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c
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$5$ |
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d
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$8$ |
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e
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$60$ |
The dot plot below shows the results of a survey of a group of people, asking them how many hours per day they spend reading. How many respondents spend no more than one hour per day reading?
The dot plot tells us the following:
of the respondents spend hours per day reading ( dots over )
of the respondents spend hour per day reading ( dot over )
of the respondents spend hours per day reading ( dots over )
of the respondents spend hour per day reading ( dot over )
of the respondents spends hours per day reading ( dots over )
Therefore, of the respondents spend no more than one hour per day reading.
A data set is represented by the dot plot above. Each dot corresponds to a single value in the data set. How many values are less or equal to $2?$
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a
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$1$ |
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b
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$3$ |
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c
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$6$ |
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d
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$5$ |
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e
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$2$ |
Jamie asked some of her friends how much time they spent walking their pets each day last week. The results are shown in the dot plot above. Each dot represents one of Jamie's friends. How many of Jamie's friends walk their pets for at least $30$ minutes daily?
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a
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$6$ |
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b
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$5$ |
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c
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$2$ |
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d
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$3$ |
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e
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$7$ |
