7th Grade Math ยท Unit 1
Read a histogram and count the values in each interval.
Bars touch
A histogram uses numerical data. The bars touch because the intervals meet.
The height of a bar is the count. Read the number at the top of the bar.
Intervals meet
Intervals include both ends. They do not overlap, and they do not leave a gap.
0 to 4 means 0, 1, 2, 3, and 4.
The total
Add the bar heights to get the number of values.
A value goes in exactly one interval.
Read one bar, or add the bar heights.
This histogram shows 12 bus ride minutes.
How many values are in 10 to 14?
count = height of the bar
count for 10 to 14 = 3
count = 3
Answer: 3
Use the bus ride histogram.
How many values are in 0 to 4?
count = height of the bar
count for 0 to 4 = 2
count = 2
Answer: 2
The bus ride histogram is shown again so you can add.
What is the total number of values?
total = sum of the bar heights
total = 2 + 3 + 3 + 2 + 2
total = 12
Answer: 12
This histogram shows the heights of 15 tomato plants.
How many values are in 10 to 14?
count = height of the bar
count for 10 to 14 = 5
count = 5
Answer: 5
Use the tomato plant histogram to find the total.
What is the total number of values?
total = sum of the bar heights
total = 1 + 3 + 5 + 4 + 2
total = 15
Answer: 15
This histogram shows pages read by 16 students.
How many values are in 20 to 29?
count = height of the bar
count for 20 to 29 = 4
count = 4
Answer: 4
Add every bar in the pages histogram.
What is the total number of values?
total = sum of the bar heights
total = 3 + 5 + 4 + 3 + 1
total = 16
Answer: 16
This histogram shows points scored by 12 players.
How many values are in 5 to 9?
count = height of the bar
count for 5 to 9 = 5
count = 5
Answer: 5
Find the total number of players in the points histogram.
What is the total number of values?
total = sum of the bar heights
total = 4 + 5 + 3
total = 12
Answer: 12
This histogram shows 15 lunch times.
How many values are in 20 to 24?
count = height of the bar
count for 20 to 24 = 3
count = 3
Answer: 3
Add the lunch time bars.
What is the total number of values?
total = sum of the bar heights
total = 2 + 5 + 5 + 3
total = 15
Answer: 15
Use the bar heights. Do not guess a count that the bars do not show.
Use the tomato plant histogram.
Which interval has the most values?
The tallest bar has the greatest count. If two heights match, those intervals are tied.
10 to 14 has the most values, with 5.
Answer: 10 to 14 has the most values, with 5.
Use the pages histogram.
Which interval has the most values?
The tallest bar has the greatest count. If two heights match, those intervals are tied.
10 to 19 has the most values, with 5.
Answer: 10 to 19 has the most values, with 5.
Use the points histogram.
Which interval has the most values?
The tallest bar has the greatest count. If two heights match, those intervals are tied.
5 to 9 has the most values, with 5.
Answer: 5 to 9 has the most values, with 5.
Use the bus ride histogram.
Which intervals are tied for the most values?
The tallest bar has the greatest count. If two heights match, those intervals are tied.
5 to 9 and 10 to 14 are tied for the most values, with 3 each.
Answer: 5 to 9 and 10 to 14 are tied for the most values, with 3 each.
Use the lunch histogram.
Which intervals are tied for the most values?
The tallest bar has the greatest count. If two heights match, those intervals are tied.
10 to 14 and 15 to 19 are tied for the most values, with 5 each.
Answer: 10 to 14 and 15 to 19 are tied for the most values, with 5 each.
Stay with the bus ride histogram.
How many values are greater than 14?
Greater than 14 leaves out 14. Use the intervals that start after 14: 15 to 19 and 20 to 24.
count = sum of those bar heights
count = 2 + 2
count = 4
Answer: 4
Stay with the tomato plant histogram.
How many values are greater than 14?
Greater than 14 leaves out 14. Use the intervals that start after 14: 15 to 19 and 20 to 24.
count = sum of those bar heights
count = 4 + 2
count = 6
Answer: 6
Stay with the pages histogram.
How many values are greater than 29?
Greater than 29 leaves out 29. Use the intervals that start after 29: 30 to 39 and 40 to 49.
count = sum of those bar heights
count = 3 + 1
count = 4
Answer: 4
Stay with the points histogram.
How many values are greater than 9?
Greater than 9 leaves out 9. Use the intervals that start after 9: 10 to 14.
count = sum of those bar heights
count = 3
count = 3
Answer: 3
Stay with the lunch histogram.
How many values are greater than 19?
Greater than 19 leaves out 19. Use the intervals that start after 19: 20 to 24.
count = sum of those bar heights
count = 3
count = 3
Answer: 3
Use the pages histogram one more time.
How many values are greater than 39?
Greater than 39 leaves out 39. Use the intervals that start after 39: 40 to 49.
count = sum of those bar heights
count = 1
count = 1
Answer: 1
Count from the list, or decide how the bars should be drawn.
count = number of values in the interval
15 to 19 means 15, 16, 17, 18, and 19.
Both ends count, and the value goes in only one interval.
The values are 16 and 18.
count = 2
Answer: 2
count = number of values in the interval
5 to 9 means 5, 6, 7, 8, and 9.
Both ends count, and the value goes in only one interval.
The values are 6, 7, and 8.
count = 3
Answer: 3
count = number of values in the interval
0 to 9 means 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.
Both ends count, and the value goes in only one interval.
The values are 5, 8, and 9.
count = 3
Answer: 3
count = number of values in the interval
0 to 4 means 0, 1, 2, 3, and 4.
Both ends count, and the value goes in only one interval.
The values are 0, 2, 3, and 4.
count = 4
Answer: 4
count = number of values in the interval
5 to 9 means 5, 6, 7, 8, and 9.
Both ends count, and the value goes in only one interval.
The values are 8 and 9.
count = 2
Answer: 2
count = number of values in the interval
20 to 24 means 20, 21, 22, 23, and 24.
Both ends count, and the value goes in only one interval.
The values are 21 and 23.
count = 2
Answer: 2
A histogram uses touching bars for numerical intervals.
0 to 4 meets 5 to 9. There is no gap and no overlap.
Yes. The bars should touch.
Answer: Yes. The bars should touch.
Histogram bars touch.
4 is the end of the first interval and 5 is the start of the next.
No. The bars should touch.
Answer: No. The bars should touch.
An interval includes both ends.
0 to 4 means 0, 1, 2, 3, and 4.
Answer: 0, 1, 2, 3, and 4.
Intervals do not overlap.
9 is in 5 to 9. The next interval starts at 10.
No. 9 belongs in only one bar.
Answer: No. 9 is only in 5 to 9.
The intervals should not leave a gap.
14 is in 10 to 14, and 15 is in 15 to 19.
They meet. There is no gap and no overlap.
Answer: They meet. 15 is in 15 to 19, and nothing between 14 and 15 is left out.
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