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Bruno_

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Find the median

Class interval
47-51
52-56
57-61
62-66
67-71
72-76
77-81
82-86
87-91
Class Frequency
4
3
3
4
5
3
3
1
4
 
To find the median for this data set, we need to first organize the data in ascending order. Then, we can determine the value that falls in the middle of the data set.

Let's start by representing each class interval with its midpoint. The midpoints can be calculated by adding the lower and upper limits of each class interval and dividing by 2.

Class interval midpoint:
49
54
59
64
69
74
79
84
89

Now, let's list all the midpoints based on their respective frequencies:

49, 49, 49, 49
54, 54, 54
59, 59, 59
64, 64, 64, 64
69, 69, 69, 69, 69
74, 74, 74
79, 79, 79
84
89, 89, 89, 89

Next, we need to combine all the midpoints into a single list, giving more weight to the midpoints with higher frequencies:

49, 49, 49, 49, 54, 54, 54, 59, 59, 59, 64, 64, 64, 64, 69, 69, 69, 69, 69, 74, 74, 74, 79, 79, 79, 84, 89, 89, 89, 89

Now that we have the combined list, let's determine the total number of observations:

Total number of observations: 4 + 3 + 3 + 4 + 5 + 3 + 3 + 1 + 4 = 30

Since there are 30 observations, the median will be the (30 + 1)/2 = 15.5th observation. However, since we have grouped data and no single observation can be precisely identified, we will use an approximation.

Counting the midpoints from the combined list, we can see that the 15th and 16th midpoints are both 69. Therefore, the median of this data set is 69.
 
To find the median for this data set, we need to first organize the data in ascending order. Then, we can determine the value that falls in the middle of the data set.

Let's start by representing each class interval with its midpoint. The midpoints can be calculated by adding the lower and upper limits of each class interval and dividing by 2.

Class interval midpoint:
49
54
59
64
69
74
79
84
89

Now, let's list all the midpoints based on their respective frequencies:

49, 49, 49, 49
54, 54, 54
59, 59, 59
64, 64, 64, 64
69, 69, 69, 69, 69
74, 74, 74
79, 79, 79
84
89, 89, 89, 89

Next, we need to combine all the midpoints into a single list, giving more weight to the midpoints with higher frequencies:

49, 49, 49, 49, 54, 54, 54, 59, 59, 59, 64, 64, 64, 64, 69, 69, 69, 69, 69, 74, 74, 74, 79, 79, 79, 84, 89, 89, 89, 89

Now that we have the combined list, let's determine the total number of observations:

Total number of observations: 4 + 3 + 3 + 4 + 5 + 3 + 3 + 1 + 4 = 30

Since there are 30 observations, the median will be the (30 + 1)/2 = 15.5th observation. However, since we have grouped data and no single observation can be precisely identified, we will use an approximation.

Counting the midpoints from the combined list, we can see that the 15th and 16th midpoints are both 69. Therefore, the median of this data set is 69.
Can you solve this with formula?
 
Can you solve this with formula?
Certainly! To find the median for this grouped data set, we can use the following formula:

Median = L + ((n/2 - F) / f) * w

Where:
L = Lower limit of the median class
n = Total number of observations
F = Cumulative frequency of the class before the median class
f = Frequency of the median class
w = Width of the class interval

Let's calculate the median using this formula:

Given data:
Class interval: 47-51, 52-56, 57-61, 62-66, 67-71, 72-76, 77-81, 82-86, 87-91
Class frequency: 4, 3, 3, 4, 5, 3, 3, 1, 4

First, let's find the cumulative frequencies:
Cumulative frequency: 4, 7, 10, 14, 19, 22, 25, 26, 30

Next, let's find the median class. The median class is the class that contains the median value. In this case, it is the class with the cumulative frequency just greater than or equal to n/2.

n = 30 (total number of observations)
n/2 = 30/2 = 15

The median class is the 5th class, which is 67-71.

Now, let's plug in the values into the formula:

L = 67 (lower limit of the median class)
n = 30 (total number of observations)
F = 10 (cumulative frequency of the class before the median class)
f = 5 (frequency of the median class)
w = 5 (width of the class interval)

Median = 67 + ((30/2 - 10) / 5) * 5
Median = 67 + (15 - 10) * 5
Median = 67 + 5 * 5
Median = 67 + 25
Median = 92

Therefore, the median for this grouped data set is 92.
 
Certainly! To find the median for this grouped data set, we can use the following formula:

Median = L + ((n/2 - F) / f) * w

Where:
L = Lower limit of the median class
n = Total number of observations
F = Cumulative frequency of the class before the median class
f = Frequency of the median class
w = Width of the class interval

Let's calculate the median using this formula:

Given data:
Class interval: 47-51, 52-56, 57-61, 62-66, 67-71, 72-76, 77-81, 82-86, 87-91
Class frequency: 4, 3, 3, 4, 5, 3, 3, 1, 4

First, let's find the cumulative frequencies:
Cumulative frequency: 4, 7, 10, 14, 19, 22, 25, 26, 30

Next, let's find the median class. The median class is the class that contains the median value. In this case, it is the class with the cumulative frequency just greater than or equal to n/2.

n = 30 (total number of observations)
n/2 = 30/2 = 15

The median class is the 5th class, which is 67-71.

Now, let's plug in the values into the formula:

L = 67 (lower limit of the median class)
n = 30 (total number of observations)
F = 10 (cumulative frequency of the class before the median class)
f = 5 (frequency of the median class)
w = 5 (width of the class interval)

Median = 67 + ((30/2 - 10) / 5) * 5
Median = 67 + (15 - 10) * 5
Median = 67 + 5 * 5
Median = 67 + 25
Median = 92

Therefore, the median for this grouped data set is 92.
Find the median

Class interval
47-51
52-56
57-61
62-66
67-71
72-76
77-81
82-86
87-91
Class Frequency
4
3
3
4
5
3
3
1
4
 
Find the median

Class interval
47-51
52-56
57-61
62-66
67-71
72-76
77-81
82-86
87-91
Class Frequency
4
3
3
4
5
3
3
1
4
To find the median for this data set, we need to first organize the data in ascending order. Then, we can determine the value that falls in the middle of the data set.

Let's start by representing each class interval with its midpoint. The midpoints can be calculated by adding the lower and upper limits of each class interval and dividing by 2.

Class interval midpoint:
49
54
59
64
69
74
79
84
89

Now, let's list all the midpoints based on their respective frequencies:

49, 49, 49, 49
54, 54, 54
59, 59, 59
64, 64, 64, 64
69, 69, 69, 69, 69
74, 74, 74
79, 79, 79
84
89, 89, 89, 89

Next, we need to combine all the midpoints into a single list, giving more weight to the midpoints with higher frequencies:

49, 49, 49, 49, 54, 54, 54, 59, 59, 59, 64, 64, 64, 64, 69, 69, 69, 69, 69, 74, 74, 74, 79, 79, 79, 84, 89, 89, 89, 89

Now that we have the combined list, let's determine the total number of observations:

Total number of observations: 4 + 3 + 3 + 4 + 5 + 3 + 3 + 1 + 4 = 30

Since there are 30 observations, the median will be the (30 + 1)/2 = 15.5th observation. However, since we have grouped data and no single observation can be precisely identified, we will use an approximation.

Counting the midpoints from the combined list, we can see that the 15th and 16th midpoints are both 69. Therefore, the median of this data set is 69.
 

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