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Warm Up. How many Lostcreek memberships were sold during the four day period? Which country club experienced the best sales?. Histograms. Section 13-5. Objectives. Previously, you have already displayed data in a stem-and-leaf plot. (Lesson 13–2).
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Warm Up How many Lostcreek memberships were sold during the four day period? Which country club experienced the best sales?
Histograms Section 13-5
Objectives Previously, you have already displayed data in a stem-and-leaf plot. (Lesson 13–2) • Today, we will display data in a histogram. • Also, we will interpret data in a histogram.
Vocabulary • histogram A histogram uses bars to display numerical data that have been organized into equal intervals
Parts of a Histogram Title Salary at the Acme Corporation y-axis units x-axis units
Interpreting a Histogram Read the ……… Title Units Number Values Intervals
Example 1 A. ELEVATIONS Use the histogram. How many states have highest points with elevations at least 3751 meters? Since 11 states have elevations in the 3751–5000 range and 1 state has an elevation in the 5001–6250 range, 11 + 1 or 12 states have highest points with elevations at least 3751 meters. Answer: 12 states
Answer: So, the percent of states with elevations above 2500 meters is or 30%. Example 1 B. ELEVATIONS Use the histogram. What percent of states contain elevations above 2500 meters? There are 22 + 13 + 3 + 11 + 1 or 50 states. There are 3 + 11 + 1 or 15 states that have elevations above 2500 meters.
Example 2 C. ELEVATIONS Use the histogram. How many states have highest points with elevations less than 2501 meters? A. 28 states B. 30 states C. 35 states D. 40 states
Example 2 D. ELEVATIONS Use the histogram. What percent of states contain elevations above 1250 meters? A. 50% B. 56% C. 60% D. 65%
Example 3 EMPLOYMENT Use the histograms. Which business sector has more states with the number of employees in the interval 1001 to 3000? The trade sector has 5 + 1 or 6 states and service sector has 8 + 3 or 11 states in the interval 1001 to 3000. Answer: So, the service sector has more.
Example 4 EATING OUT Use the histograms. Which coast has more people spending at least $60 weekly? East Coast West Coast C. Both have an equal number of people spending at least $60 weekly. D. cannot be determined
Great, we can read a histogram, but how do we create a histogram? • Histograms are bar graphs where the bars touch. • Histograms also measure frequency. • Therefore, we need to create a frequency table of the data. • We must also figure out what size to make the intervals. We should have at least 5 – 7 intervals.
Example-Test Scores on an 11th Grade Science Test • The test scores on an 11th grade science test: 58, 91, 78, 84, 93, 65, 73, 69, 77, 83, 80, 90, 85, 74, 61, 71, 83, 76, 63, 70 • Step 1: Find the range • 93-58=35 • Step 2: Determine the size of the intervals • 35÷7=5 (the intervals will 5 scores) • Step 3: Create a frequency table • Step 4: On the x-axis, space out your intervals; on the y-axis, put the frequency • Step 5: Label the axes • Step 6: Draw the graph
Here’s the Histogram Science Test Scores 4 3 2 1 0 F requency 58-62 63-67 68-72 73-77 78-82 83-87 88-93 Scores