Data Analysis Flashcards

What is the median of the following data set: 12, 15, 18, 20, 22?

Answer: 18

The median is the middle value in a data set when it is ordered from least to greatest. In the given set (12, 15, 18, 20, 22), there are five numbers. The middle number, with two numbers before it and two numbers after it, is 18.

A graph shows monthly sales figures for a year. Which of the following is NOT a valid conclusion you can draw?

Answer: Sales figures for the next year will be higher.

A graph displays past or present data and trends, allowing for analysis of what has already occurred. However, it cannot definitively predict future events or sales figures. While past trends might suggest possibilities, making a definitive statement about future sales is a speculative conclusion, not a valid one directly drawn from the presented data.

If a bar graph shows a category with zero frequency, what does this indicate?

Answer: No observations fall into that category.

In a bar graph, a category with zero frequency indicates that no data points or observations fall into that specific category. This means that, within the scope of the data collected, that particular category simply did not occur or was not represented. It is a valid data point showing absence, not incompleteness or inaccuracy of the graph itself.

A survey showed 40% of respondents prefer brand A, 35% prefer brand B, and 25% prefer brand C. If there were 200 respondents, how many preferred brand B?

Answer: 70

To find out how many respondents preferred brand B, you need to calculate 35% of the total number of respondents. With 200 respondents, 35% of 200 is (0.35 * 200). This calculation yields 70 respondents.

Which type of graph is best suited for showing the proportion of different categories in a data set?

Answer: Pie chart

A pie chart is specifically designed to show the proportion of different categories within a whole data set. Each 'slice' of the pie represents a category, and its size is proportional to the percentage it contributes to the total. This visual representation makes it easy to compare the relative sizes of different parts.