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At the end of each year, the Harcar Corporation assigns a rating to each member of its sales staff. The sales ratings are based on the mean (μ) and standard deviation (σ) for the individual sales totals for the year. The rating is computed by applying the following formula and then rounding the result to the nearest integer.
\(\text{Individual rating} = \frac{\text{individual total} - \mu}{\sigma}\)
Sales staff are considered for promotion if their rating is 3. The graph shows the ratings for the entire sales staff for the years 2009, 2010, and 2011.
Sales staff are considered for promotion if their rating is 3. The graph shows the ratings for the entire sales staff for the years 2009, 2010, and 2011.
| Text Component | Literal Content | Simple Interpretation |
|---|---|---|
| Company & Process | At the end of each year, the Harcar Corporation assigns a rating to each member of its sales staff. | Yearly performance ratings for all salespeople are assigned by the company. |
| Rating Basis | The sales ratings are based on the mean (\(\mu\)) and standard deviation (\(\sigma\)) for the individual sales totals for the year. | Ratings reflect how each sales total compares to the average and spread for that year. |
| Rating Formula | Individual rating = \(\frac{\text{individual total} - \mu}{\sigma}\), rounded to the nearest integer. | Each person's rating measures their performance in standard deviations from the mean. |
| Promotion Criterion | Sales staff are considered for promotion if their rating is 3. | Only employees at least 3 SD above average are eligible for promotion. |
| Years Shown | The graph shows the ratings for the entire sales staff for the years 2009, 2010, and 2011. | The diagram covers employee ratings distributions for three consecutive years. |
| Chart Component | What Is Shown | Interpretation |
|---|---|---|
| Chart Type | Grouped bar chart (one group each for 2009, 2010, 2011) | Compares distributions across three years |
| X-axis | Ratings from -3 to 3 | Range: far below average to far above average |
| Y-axis | Number of employees (0-100) | Measures how many staff received each rating |
| Distribution Shape | Bell curve, peak at 0 | Most staff are average performers |
| Count at 0 | 104 (2009), 101 (2010), 86 (2011) | Plurality of staff are rated average each year |
| Counts at 3 | 3 (2009), 2 (2010), 1 (2011) | Very few achieve promotion threshold |
| Total Staff | 251 (2009), 296 (2010), 219 (2011) | 2010: largest group; 2011: smallest |
The graph [BLANK] the claim that the sales staff had the fewest members in 2010.
The graph [BLANK] the claim that, as a group, the staff's total sales were highest in 2011.
The graph allows us to determine total staff each year (from bar heights), showing 2010 had the most and 2011 the fewest staff, refuting the claim in Question 1. However, because the data are standardized within each year, the chart gives absolutely no information about actual sales figures, so it cannot support or refute claims about which year had the highest total sales, as in Question 2.
The two questions are independent because Question 1 is about staff headcount (which is encoded in the sum of the bar heights for each year), while Question 2 is about total sales (which the chart does not display at all, as it only shows standardized scores). The answer to one does not affect the reasoning or answer to the other.