Standard deviation, raw score etc

In summary, the test has a mean of 80, a standard deviation of 5, and a standard error of measurement of 3. The raw score is the same as the observed score, and the true score cannot be determined due to unknown error. The confidence interval at 68% confidence level is from 77 to 83, and the confidence interval at 95% confidence level is from 74.12 to 85.88.
  • #1
saharalynne
1
0
-3 SD -2 SD -1 SD 80 +1SD +2 SD +3 SD
mean
65 70 75 85 90 95

The test has a mean of 80, a standard deviation of 5 and a standard error of measurement of 3.
Information given: Mean = 80 SD = 5 SEM = 3 Jim’s score = 85

I need to know the raw score, observed score, true score, ci for 68 and 95
 
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  • #2
saharalynne said:
-3 SD -2 SD -1 SD 80 +1SD +2 SD +3 SD
mean
65 70 75 85 90 95The test has a mean of 80, a standard deviation of 5 and a standard error of measurement of 3.
Information given: Mean = 80 SD = 5 SEM = 3 Jim’s score = 85

I need to know the raw score, observed score, true score, ci for 68 and 95

Hi saharalynne! Welcome to MHB! (Smile)

The raw score is the original untransformed score, which is the same as the observed score.
We can never know the true score, since what we measure always contains an unknown error.

The confidence interval (CI) at confidence level 68% is the interval from Mean - SEM to Mean + SEM.
And the CI at confidence level 95% is the interval from Mean - 1.96 x SEM to Mean + 1.96 x SEM.

Can you tell what each of those are? (Wondering)
 

FAQ: Standard deviation, raw score etc

What is standard deviation?

Standard deviation is a measure of how much the data values vary from the mean or average of a set of numbers. It is calculated by finding the square root of the variance.

How is standard deviation calculated?

To calculate standard deviation, you first find the mean of the data set. Then, for each data point, you subtract the mean and square the result. Next, find the average of those squared differences. Finally, take the square root of that average to get the standard deviation.

What is a raw score?

A raw score is an unaltered measurement of an individual's performance on a particular assessment or test. It is usually the total number of correct answers or points earned.

How is a raw score used in statistics?

Raw scores are often used to calculate other statistical measures, such as standard deviation, mean, and percentile ranks. They can also be used to compare an individual's performance to a group or to track progress over time.

What is the difference between population standard deviation and sample standard deviation?

Population standard deviation is calculated using the entire set of data from a population, while sample standard deviation is calculated using a smaller subset of data from a larger population. Sample standard deviation is typically used when the entire population cannot be measured or is too large to analyze.

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