Question 1: Calculate the frequency for the class interval 20-29 if the total data is 150 and the histogram bar height for this interval is 4 units.

Answer: 30

Question 2: A histogram shows that the bar for ages 30-39 has a height of 5 units. If the total number of data points is 200, what is the frequency for this age group?

Answer: 50

Question 3: Find the total number of data points represented if the histogram has the following frequencies: 25, 40, 35, 20, and 30.

Answer: 150

Question 4: A histogram shows the frequency for classes 10-19 (12), 20-29 (18), 30-39 (25), 40-49 (20). What is the total number of data points?

Answer: 75

Question 5: Construct a histogram bar for the class 50-59 with a frequency of 45, if each unit height on the grid represents 5 data points.

Answer: 9 units

Question 6: A histogram shows a bar height of 6 units for the class 60-69. If each unit represents 4 data points, what is the frequency for this class?

Answer: 24

Question 7: A histogram has the following class intervals and bar heights: 0-9 (2 units), 10-19 (4 units), 20-29 (6 units). If the total data is 180, find the frequency for 20-29.

Answer: 60

Question 8: A histogram shows the class 40-49 with a bar height of 7 units. If the total number of data points is 350 and each unit represents 10 data points, what is the frequency for this class?

Answer: 70

Question 9: In a real-world scenario, a histogram represents the number of cars passing a checkpoint each hour. The bar for 8-9 am is 5 units high, and each unit equals 8 cars. How many cars passed between 8-9 am?

Answer: 40

Question 10: Identify and correct the mistake: A histogram shows that the bar for 50-59 has a height of 10 units, and each unit represents 5 data points. The total data points are given as 250. The student claims the total data is 500.

Answer: Incorrect; total data points are 10 units x 5 = 50, not 500.

Question 11: A challenge: The histogram for class intervals 0-9, 10-19, 20-29, 30-39 shows bar heights of 3, 6, 9, and 12 units respectively. If each unit is 4 data points, calculate the total number of data points. Then, determine the percentage of data in the 20-29 class.

Answer: Total = (3+6+9+12) x 4 = 96; Percentage in 20-29 = (9 x 4 / 96) x 100 = 37.5%