Solution
Understanding the Set
In this set we need to fill a table, in which we need to find the ratings given by five restaurants, coded R1, R2, R3, R4, and R5 to Ullas, Vasu, Waman, Xavier, and Yusuf on a scale of 1 to 5, using the data given in the question.
Also, the set gives us a table that provides the median, mode, mean, and range of ratings given by all five raters.
Concepts
| Concept | Explanation | Example |
|---|---|---|
| Median | The middle value when data is arranged in ascending or descending order. | Data: 2, 1, 4, 3, 5 → Ordered: 1, 2, 3, 4, 5 → Median: 3 |
| Mode | The value that appears most frequently in a dataset. | Data: 2, 4, 5, 5, 6, 7 → Mode: 5 |
| Mean | The average value of the dataset. | Data: 2, 4, 6, 8, 10 → Sum = 30 → Mean = 30/5 = 6 |
| Range | The difference between the maximum and minimum values. | Data: 21, 6, 17, 18, 12, 8, 4, 13 → Range = 21 − 4 = 17 |
| U | V | W | X | Y | Total | |
|---|---|---|---|---|---|---|
| R1 | 17 | |||||
| R2 | 11 | |||||
| R3 | 19 | |||||
| R4 | 14 | |||||
| R5 | 17 | |||||
| Total |
Summary Table
| Ullas | Vasu | Waman | Xavier | Yusuf | |
|---|---|---|---|---|---|
| Mean | |||||
| Median | |||||
| Modal | |||||
| Range |
Given that the means of the ratings given by R1, R2, R3, R4 and R5 were 3.4, 2.2, 3.8, 2.8 and 3.4 respectively.
Total Ratings Given by Restaurants
| U | V | W | X | Y | Total | |
|---|---|---|---|---|---|---|
| R1 | 17 | |||||
| R2 | 11 | |||||
| R3 | 19 | |||||
| R4 | 14 | |||||
| R5 | 17 | |||||
| Total | 11 | 19 | 17 | 18 | 13 |
Summary Table
| Ullas | Vasu | Waman | Xavier | Yusuf | |
|---|---|---|---|---|---|
| Mean | |||||
| Median | |||||
| Modal | |||||
| Range |
Also from the table we know mean ratings given by U, V, W, X, Y which is 2.2, 3.8, 3.4, 3.6, 2.6.
Using the same concept as before we can find the sum of ratings given to them:
Total Ratings Given to Each Person
Restaurant Ratings Table (after using clues)
| U | V | W | X | Y | Tot | |
|---|---|---|---|---|---|---|
| R1 | 1 | 5 | ||||
| R2 | 1 | 5 | 1 | |||
| R3 | 5 | 5 | 1 | |||
| R4 | ||||||
| R5 | 5 | |||||
| Total | 11 | 19 | 17 | 18 | 13 | |
| Med | 2 | 4 | 4 | 4 | 3 | |
| Mod | 2 | 4 | 5 | 5 | 1&4 | |
| Range | 3 | 3 | 4 | 4 | 3 |
Now, using clues given in the question:
(a) R1 awarded a rating of 5 to Waman, as did R2 to Xavier, R3 to Waman and Xavier, and R5 to Vasu.
(b) R1 awarded a rating of 1 to Ullas, as did R2 to Waman and Yusuf, and R3 to Yusuf.
We fill the table accordingly.
Restaurant Ratings Table (U deduced)
| U | V | W | X | Y | Tot | |
|---|---|---|---|---|---|---|
| R1 | 1 | 5 | ||||
| R2 | 1 | 5 | 1 | |||
| R3 | 5 | 5 | 1 | |||
| R4 | ||||||
| R5 | 5 | |||||
| Total | 11 | 19 | 17 | 18 | 13 | |
| Ratings | 1,2,2,2,4 | |||||
| Med | 2 | 4 | 4 | 4 | 3 | |
| Mod | 2 | 4 | 5 | 5 | 1&4 | |
| Range | 3 | 3 | 4 | 4 | 3 |
Now, consider U.
Given: median = 2, mode = 2 and range = 3.
So ratings are of the form: 1, a, 2, b, 4 (median 2, range 3 → max 4).
Sum condition: .
For mode = 2, take . Hence U’s ratings are 1, 2, 2, 2, 4 (in some order).
Restaurant Ratings Table (U, V placed)
| U | V | W | X | Y | Tot | |
|---|---|---|---|---|---|---|
| R1 | 1 | 5 | ||||
| R2 | 1 | 5 | 1 | |||
| R3 | 5 | 5 | 1 | |||
| R4 | ||||||
| R5 | 5 | |||||
| Total | 11 | 19 | 17 | 18 | 13 | |
| Ratings | 1,2,2,2,4 | 2,4,4,4,5 | ||||
| Med | 2 | 4 | 4 | 4 | 3 | |
| Mod | 2 | 4 | 5 | 5 | 1&4 | |
| Range | 3 | 3 | 4 | 4 | 3 |
V: median = 4, mode = 4, range = 3
Form: 2, a, 4, b, 5; sum ; mode 4 → → 2, 4, 4, 4, 5.
Restaurant Ratings Table (U, V, W placed)
| U | V | W | X | Y | Tot | |
|---|---|---|---|---|---|---|
| R1 | 1 | 5 | ||||
| R2 | 1 | 5 | 1 | |||
| R3 | 5 | 5 | 1 | |||
| R4 | ||||||
| R5 | 5 | |||||
| Total | 11 | 19 | 17 | 18 | 13 | |
| Ratings | 1,2,2,2,4 | 2,4,4,4,5 | 1,2,4,5,5 | |||
| Med | 2 | 4 | 4 | 4 | 3 | |
| Mod | 2 | 4 | 5 | 5 | 1&4 | |
| Range | 3 | 3 | 4 | 4 | 3 |
W: median = 4, mode = 5, range = 4
Form: 1, a, 4, 5, 5; sum → 1, 2, 4, 5, 5.
Restaurant Ratings Table (U, V, W, X placed)
| U | V | W | X | Y | Tot | |
|---|---|---|---|---|---|---|
| R1 | 1 | 5 | ||||
| R2 | 1 | 5 | 1 | |||
| R3 | 5 | 5 | 1 | |||
| R4 | ||||||
| R5 | 5 | |||||
| Total | 11 | 19 | 17 | 18 | 13 | |
| Ratings | 1,2,2,2,4 | 2,4,4,4,5 | 1,2,4,5,5 | 1,3,4,5,5 | ||
| Med | 2 | 4 | 4 | 4 | 3 | |
| Mod | 2 | 4 | 5 | 5 | 1&4 | |
| Range | 3 | 3 | 4 | 4 | 3 |
X: median = 4, mode = 5, range = 4
Form: 1, a, 4, 5, 5; sum → 1, 3, 4, 5, 5.
Restaurant Ratings Table (all distributions fixed)
| U | V | W | X | Y | Tot | |
|---|---|---|---|---|---|---|
| R1 | 1 | 5 | ||||
| R2 | 1 | 5 | 1 | |||
| R3 | 5 | 5 | 1 | |||
| R4 | ||||||
| R5 | 5 | |||||
| Total | 11 | 19 | 17 | 18 | 13 | |
| Ratings | 1,2,2,2,4 | 2,4,4,4,5 | 1,2,4,5,5 | 1,3,4,5,5 | 1,1,3,4,4 | |
| Med | 2 | 4 | 4 | 4 | 3 | |
| Mod | 2 | 4 | 5 | 5 | 1&4 | |
| Range | 3 | 3 | 4 | 4 | 3 |
Y: median = 3, mode = 1 & 4, range = 3 → 1, 1, 3, 4, 4.
Now, consider column R3:
The two missing entries should add up to (only possibility: 4 + 4).
Thus we can place U = 4 in R3’s column and one 4 in V’s column for R3.
Therefore, in row R2, the missing entry should be
.
Restaurant Ratings Table (penultimate fill)
| U | V | W | X | Y | Tot | |
|---|---|---|---|---|---|---|
| R1 | 1 | 4 | 5 | |||
| R2 | 2 | 2 | 1 | 5 | 1 | |
| R3 | 4 | 4 | 5 | 5 | 1 | |
| R4 | 2 | 4 | 2/4 | |||
| R5 | 2 | 5 | 4/2 | |||
| Total | 11 | 19 | 17 | 18 | 13 | |
| Ratings | 1,2,2,2,4 | 2,4,4,4,5 | 1,2,4,5,5 | 1,3,4,5,5 | 1,1,3,4,4 | |
| Med | 2 | 4 | 4 | 4 | 3 | |
| Mod | 2 | 4 | 5 | 5 | 1&4 | |
| Range | 3 | 3 | 4 | 4 | 3 |
Consider row R1:
Missing elements must add to → (3 + 4) or (4 + 3). — (1)
Consider R5: the three missing elements should add to → 2 + 4 + 4 or 4 + 3 + 3.
But (1) requires a 3, so the consistent placement leads to resolving R1 and then R4/R5.
Completed Restaurant Ratings Table
| U | V | W | X | Y | Tot | |
|---|---|---|---|---|---|---|
| R1 | 1 | 4 | 5 | 3 | 4 | |
| R2 | 2 | 2 | 1 | 5 | 1 | |
| R3 | 4 | 4 | 5 | 5 | 1 | |
| R4 | 2 | 4 | 4 | 1 | 3 | |
| R5 | 2 | 5 | 2 | 4 | 4 | |
| Total | 11 | 19 | 17 | 18 | 13 | |
| Med | 2 | 4 | 4 | 4 | 3 | |
| Mod | 2 | 4 | 5 | 5 | 1&4 | |
| Range | 3 | 3 | 4 | 4 | 3 |
So we can fill row R1 as 3 and 4, and the remaining values in R4 and R5 to match all given totals and summary statistics.
Restaurant Ratings Table
| U | V | W | X | Y | Tot | |
|---|---|---|---|---|---|---|
| R1 | 1 | 4 | 5 | 3 | 4 | |
| R2 | 2 | 2 | 1 | 5 | 1 | |
| R3 | 4 | 4 | 5 | 5 | 1 | |
| R4 | 2 | 4 | 4 | 1 | 3 | |
| R5 | 2 | 5 | 2 | 4 | 4 | |
| Total | 11 | 19 | 17 | 18 | 13 | |
| Med | 2 | 4 | 4 | 4 | 3 | |
| Mod | 2 | 4 | 5 | 5 | 1&4 | |
| Range | 3 | 3 | 4 | 4 | 3 |
=> Ratings give by R3 are 1, 4, 4, 5, 5 => Median = 4
More from this set:
Question 6