What standard score is 1.5 SD below the mean?
What standard score is 1.5 SD below the mean?
77.5 5.5
| Standard Deviation/Standard/Scaled Score Correspondence | ||
|---|---|---|
| Standard Deviation (SD) | Standard Score | Scaled Score |
| 1 SD below mean | Between 70 and 85 | Between 4 and 7 |
| 1.5 SD below mean | 77.5 | 5.5 |
| 2 SD below mean | 70 or below | 4 or below |
How do you find 1.5 standard deviations below the mean?
If 1 standard deviation is 10kg and the mean is 400kg, then 415kg is 1.5 standard deviations. This equation takes one half of the difference between two standard deviations and one standard deviation, then adds it to the first standard deviation.
What percentage is 1.5 standard deviations below the mean?
It’s about 87%.
What is a standard deviation of 1.5 mean?
In the second graph, the standard deviation is 1.5 points, which, again, means that two-thirds of students scored between 8.5 and 11.5 (plus or minus one standard deviation of the mean), and the vast majority (95 percent) scored between 7 and 13 (two standard deviations).
What score is 1.5 standard deviations above the mean?
A z-score of 1.5 is 1.5 standard deviations above and below the mean. A z-score of 0 is no standard deviations above or below the mean (it’s equal to the mean).
What percentiles are average and below average?
Different publishers use different labels for the same scores. For example, a standard score of 85 (16th percentile rank) on a test may be “average,” “low average,” or even “below average,” depending on the test publisher.
How do you find the standard deviation below the mean?
In stats terminology, we would say that a score of 63 falls exactly “one standard deviation above the mean.” Similarly, we could subtract the standard deviation from the mean (58 – 5 = 53) to find the score that falls one standard deviation below the mean.
How many are actually within 1.5 SDs of the average?
The percentage of men with heights between 66 inches and 72 inches is exactly equal to the area between 66 inches and 72 inches under the histogram. This percentage is approximately equal to the area between -1 and 1 under the normal curve. 350 is 1.5 SDs below the average.
What does a standard deviation of 1.7 mean?
The z score is not ‘the number of standard deviations’. Instead the z-score of a value is the number of standard deviations that value is above the mean. A z-score of 1.7 is 1.7 standard deviations above the mean. A z score of -1 is one standard deviation below the mean, and so on.
What proportion of the data from a normal distribution is within 1.5 standard deviations of the mean?
0.866
The answer is ≈0.866 is the proportion of values within 1.5 standard deviations of the mean.
Is 78 1.5 standard deviations below the mean?
Language quotient or standard score of 78-85. 7-15th percentile. 1.5 to 2 standard deviations below the mean standard score. Language quotient or standard score of 70-77.