BKSB Data and Statistical Interpretation 5

Question 1

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?

Accepted Answer

30–39

Answer

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

Question 2

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

Accepted Answer

37.5

Answer

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

Question 3

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

Accepted Answer

25

Answer

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

Question 4

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?

Accepted Answer

Generally increasing

Answer

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

Question 5

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

Accepted Answer

15

Answer

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

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