The following appear on a physician's intake form. Identify the level of measurement of the data. \( \begin{array}{ll}\text { (a) Weight } & \text { (b) Allergies } \\ \text { (c) Year of birth } & \text { (d) Happiness level (scale of } 0 \text { to 10) }\end{array} \)

To identify the level of measurement for each item on the physician's intake form, we can categorize them according to the four levels of measurement: nominal, ordinal, interval, and ratio. (a) **Weight**: This is a ratio level of measurement. It has a true zero point (0 weight means no weight) and allows for meaningful comparisons (e.g., one person can weigh twice as much as another). (b) **Allergies**: This is a nominal level of measurement. Allergies are categorical data that can be classified into distinct groups (e.g., peanut allergy, pollen allergy) without any inherent order. (c) **Year of birth**: This is an interval level of measurement. While it has meaningful differences between values (e.g., the difference between 1980 and 1990 is the same as between 1990 and 2000), it does not have a true zero point in the context of measuring age (the year 0 does not represent the absence of time). (d) **Happiness level (scale of 0 to 10)**: This is an ordinal level of measurement. The happiness scale has a meaningful order (0 being the lowest and 10 being the highest), but the differences between the levels may not be consistent or meaningful (the difference in happiness between 3 and 4 may not be the same as between 8 and 9). In summary: - (a) Weight: Ratio - (b) Allergies: Nominal - (c) Year of birth: Interval - (d) Happiness level (scale of 0 to 10): Ordinal