a number line shows the ages (in years) that people go to two different movies.

movie 1
1 1 0 3 1 1 2 0 1 1 0 1 1 0 0 1 1 0 1 1 0 1 0 1 0 0 1
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
movie 2
0 1 0 0 1 0 2 0 1 0 2 1 1 2 0 0 3 0 1 1 0 1 0 1 1 0 1
24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

The dot plots show the ages, in years, of people watching two movies at a local theater. Find the median age of the people who watched each movie.

The median age of the people who watched Movie 1 is __.
The median age of the people who watched Movie 2 is __.

1 answer

To find the median age of the people who watched each movie, we first need to determine the total frequency of ages indicated in the dot plots for each movie.

Movie 1

Here is the age frequency breakdown based on the provided data:

  • 17: 1
  • 18: 1
  • 19: 0
  • 20: 3
  • 21: 1
  • 22: 1
  • 23: 2
  • 24: 0
  • 25: 1
  • 26: 1
  • 27: 0
  • 28: 1
  • 29: 1
  • 30: 0
  • 31: 1
  • 32: 1
  • 33: 0
  • 34: 1
  • 35: 1
  • 36: 0
  • 37: 1
  • 38: 1
  • 39: 0
  • 40: 1
  • 41: 0
  • 42: 1
  • 43: 0

Now, we tally the total number of attendees: 1 + 1 + 0 + 3 + 1 + 1 + 2 + 0 + 1 + 1 + 0 + 1 + 1 + 0 + 1 + 1 + 0 + 1 + 1 + 0 + 1 + 0 + 1 + 0 + 0 + 1 = 29.

The sorted ages for Movie 1 (based on the counts) are as follows:

  • 17, 18, 20, 20, 20, 21, 22, 23, 23, 25, 26, 28, 29, 31, 32, 34, 35, 37, 38, 40, 42,

To find the median of 29 attendees:

  • The median is the middle value. Since the total count is odd (29), the median is the 15th value in the sorted list.

Counting to the 15th value:

  1. 17
  2. 18
  3. 20
  4. 20
  5. 20
  6. 21
  7. 22
  8. 23
  9. 23
  10. 25
  11. 26
  12. 28
  13. 29
  14. 31
  15. 32 (the median for Movie 1)

Movie 2

Next, we sum the ages from Movie 2 frequency data:

  • 24: 0
  • 25: 1
  • 26: 0
  • 27: 1
  • 28: 0
  • 29: 2
  • 30: 0
  • 31: 1
  • 32: 2
  • 33: 1
  • 34: 1
  • 35: 0
  • 36: 1
  • 37: 0
  • 38: 0
  • 39: 3
  • 40: 0
  • 41: 1
  • 42: 1
  • 43: 0
  • 44: 1
  • 45: 0
  • 46: 0
  • 47: 0
  • 48: 1
  • 49: 0
  • 50: 0

Totaling the counts: 0 + 1 + 0 + 1 + 0 + 2 + 0 + 1 + 2 + 1 + 1 + 0 + 1 + 0 + 0 + 3 + 0 + 1 + 1 + 0 + 1 + 0 + 0 + 0 + 1 + 0 + 0 = 20.

Sorting the ages: The ages sorted based on the counts for the total of 20 attendees are:

  • 25, 27, 29, 29, 31, 32, 32, 33, 34, 36, 39, 39, 39, 41, 42, 44, 48

To find the median of 20 people:

  • The median is the average of the 10th and 11th values.

Counting to find the 10th and 11th values:

  1. 25
  2. 27
  3. 29
  4. 29
  5. 31
  6. 32
  7. 32
  8. 33
  9. 34
  10. 36 (10th value)
  11. 39 (11th value)

Now calculate the median: \[ \text{Median} = \frac{36 + 39}{2} = 37.5 \]

Final Results

  • The median age of the people who watched Movie 1 is 32.
  • The median age of the people who watched Movie 2 is 37.5.