Data and Statistical Interpretation Flashcards

A frequency distribution table shows ages 20–29 (freq 8), 30–39 (freq 14), 40–49 (freq 10), 50–59 (freq 8). Which class interval is the modal class?

Answer: 30–39

The modal class is the interval with the highest frequency, which is 30–39 with 14.

A survey asks 150 people about their exercise habits. Results shown in a pie chart: 'Daily' = 90°. How many people exercise daily?

Answer: 37.5

90° out of 360° = 25% of 150 = 0.25 × 150 = 37.5 people.

A box plot shows: minimum = 10, lower quartile = 20, median = 30, upper quartile = 45, maximum = 60. What is the interquartile range?

Answer: 25

IQR = upper quartile − lower quartile = 45 − 20 = 25.

A time series graph shows weekly website visits: Week 1=200, Week 2=250, Week 3=230, Week 4=280, Week 5=310. What is the trend?

Answer: Generally increasing

Despite a slight dip in Week 3, the overall direction is upward, showing a generally increasing trend.

A grouped frequency table has total frequency 60. The relative frequency of one class is 0.25. How many values are in that class?

Answer: 15

Frequency = relative frequency × total = 0.25 × 60 = 15.

Two data sets have the same mean of 50. Set A has a range of 10 and Set B has a range of 40. What can you conclude?

Answer: Set B has more spread/variation than Set A

A larger range indicates greater spread; Set B's range of 40 means its values vary more widely.

A comparative bar chart shows that in 2023, Product X sold 480 units and Product Y sold 320 units. What is the ratio of X to Y sales in simplest form?

Answer: 3:2

480:320 simplifies by dividing both by 160 → 3:2.