Review: check 1
Difficulty: ★★☆Info
Maths4U Original · Short practice
The \(\displaystyle n=16\) observations X have mean 13 and population variance 14. Define \(Y=4X+18\). A second disjoint group has 18 Y-values with mean 74.
Find the mean of Y.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Review: review variant 1
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 mean of Y.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Review: check 2
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 variance of Y.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Review: review variant 2
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 variance of Y.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Review: check 3
Difficulty: ★★☆Info
Maths4U Original · Short practice
A discrete frequency table is shown.
| Value | Frequency |
|---|---|
| 3 | 16 |
| 6 | 30 |
| 9 | 47 |
| 12 | 18 |
Find the number of observations.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Review: review variant 3
Difficulty: ★★☆Info
Maths4U Original · Short practice
A discrete frequency table is shown.
| Value | Frequency |
|---|---|
| 4 | 17 |
| 8 | 32 |
| 12 | 50 |
| 16 | 19 |
Find the number of observations.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Review: check 4
Difficulty: ★★☆Info
Maths4U Original · Short practice
Measurements of duration t, in seconds, are grouped below.
| Class (seconds) | Frequency |
|---|---|
| \(0\le t<4\) | 19 |
| \(4\le t<12\) | 35 |
| \(12\le t<24\) | 51 |
Find the number of observations with t below the last class boundary before the final class.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.
Review: review variant 4
Difficulty: ★★☆Info
Maths4U Original · Short practice
Measurements of duration t, in seconds, are grouped below.
| Class (seconds) | Frequency |
|---|---|
| \(0\le t<5\) | 20 |
| \(5\le t<15\) | 37 |
| \(15\le t<30\) | 54 |
Find the number of observations with t below the last class boundary before the final class.
Enter one number or fraction. Use at least six decimal places when needed; a distribution calculator may be used for probabilities.