Questions: Basic Skills and Concepts Statistical Literacy and Critical Thinking 1. McDonald's Dinner Service Times Refer to the accompanying table summarizing service times (seconds) of McDonald's dinners. How many individuals are included in the summary? Is it possible to identify the exact values of all of the original service times? 2. McDonald's Dinner Service Times Refer to the accompanying frequency distribution. What problem would be created by using classes of 60-120,120-180, ..., 300-360? 3. Relative Frequency Distribution Use percentages to construct the relative frequency distribution corresponding to the accompanying frequency distribution for McDonald's dinner service times. 4. What's Wrong? Heights of adult males are known to have a normal distribution, as described in this section. A researcher claims to have randomly selected adult males and measured their heights with the resulting relative frequency distribution as shown here. Identify two major flaws with these results.

Solution Steps

1. To determine how many individuals are included in the summary, we need to sum up the frequencies from the given table. Since the exact values of the original service times are not provided, it is not possible to identify them from the summary alone.

2. Using classes of $60-120, 120-180, \ldots, 300-360$ could create overlapping intervals, which would make it difficult to categorize data points that fall on the boundaries of these intervals. This could lead to ambiguity in the classification of data.

3. To construct the relative frequency distribution, we need to convert the frequencies into percentages. This involves dividing each frequency by the total number of observations and then multiplying by 100 to get the percentage.

To find the total number of individuals, sum the frequencies from the frequency distribution: \[ 5 + 10 + 15 + 20 + 25 = 75 \] Thus, the total number of individuals is \(75\).

To convert the frequencies into relative frequencies (percentages), divide each frequency by the total number of individuals and multiply by 100:

• For the class \(60-120\): \[ \left(\frac{5}{75}\right) \times 100 = 6.67\% \]
• For the class \(120-180\): \[ \left(\frac{10}{75}\right) \times 100 = 13.33\% \]
• For the class \(180-240\): \[ \left(\frac{15}{75}\right) \times 100 = 20.00\% \]
• For the class \(240-300\): \[ \left(\frac{20}{75}\right) \times 100 = 26.67\% \]
• For the class \(300-360\): \[ \left(\frac{25}{75}\right) \times 100 = 33.33\% \]

Final Answer