Variance and standard deviation: check 1
Difficulty: ★★☆Info
Maths4U Original · Short practice
The complete data set, measured in minutes, is \(14,17,17,20,23,26,26,29,35\). Treat these nine observations as a population.
| Stem | Leaf |
|---|---|
| 1 | 4 7 7 |
| 2 | 0 3 6 6 9 |
| 3 | 5 |
Key: 2 | 7 represents 27 minutes.
Find the mean in minutes.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Variance and standard deviation: review variant 1
Difficulty: ★★☆Info
Maths4U Original · Short practice
The complete data set, measured in minutes, is \(15,19,19,23,27,31,31,35,43\). Treat these nine observations as a population.
| Stem | Leaf |
|---|---|
| 1 | 5 9 9 |
| 2 | 3 7 |
| 3 | 1 1 5 |
| 4 | 3 |
Key: 2 | 7 represents 27 minutes.
Find the mean in minutes.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Variance and standard deviation: check 2
Difficulty: ★★☆Info
Maths4U Original · Short practice
The complete data set, measured in minutes, is \(15,19,19,23,27,31,31,35,43\). Treat these nine observations as a population.
| Stem | Leaf |
|---|---|
| 1 | 5 9 9 |
| 2 | 3 7 |
| 3 | 1 1 5 |
| 4 | 3 |
Key: 2 | 7 represents 27 minutes.
Find the population variance in square minutes.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Variance and standard deviation: review variant 2
Difficulty: ★★☆Info
Maths4U Original · Short practice
The complete data set, measured in minutes, is \(16,17,17,18,19,20,20,21,23\). Treat these nine observations as a population.
| Stem | Leaf |
|---|---|
| 1 | 6 7 7 8 9 |
| 2 | 0 0 1 3 |
Key: 2 | 7 represents 27 minutes.
Find the population variance in square minutes.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Variance and standard deviation: check 3
Difficulty: ★★☆Info
Maths4U Original · Short practice
The \(\displaystyle n=17\) observations X have mean 14 and population variance 15. Define \(Y=2X+19\). A second disjoint group has 19 Y-values with mean 51.
Find the sum of Y in the first group.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Variance and standard deviation: review variant 3
Difficulty: ★★☆Info
Maths4U Original · Short practice
The \(\displaystyle n=18\) observations X have mean 15 and population variance 16. Define \(Y=3X+20\). A second disjoint group has 20 Y-values with mean 69.
Find the sum of Y in the first group.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Variance and standard deviation: check 4
Difficulty: ★★☆Info
Maths4U Original · Short practice
The \(\displaystyle n=18\) observations X have mean 15 and population variance 16. Define \(Y=3X+20\). A second disjoint group has 20 Y-values with mean 69.
Find the mean of all Y-values in both groups.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Variance and standard deviation: review variant 4
Difficulty: ★★☆Info
Maths4U Original · Short practice
The \(\displaystyle n=19\) observations X have mean 16 and population variance 17. Define \(Y=4X+21\). A second disjoint group has 21 Y-values with mean 89.
Find the mean of all Y-values in both groups.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.