Standardisation Flashcards
If a child scores 4 on an age-normed test that uses a Stanine scale (higher scores = better reading), then what does this mean?
(a) They are better than the average child their own age.
(b) They are similar to the average child their own age.
(c) They are worse than the average child their own age.
(d) They are similar to the average child who is a year younger than them.
The answer was c. See Lecture 2. A stanine has 9 categories, where 5 includes the average (assuming a normal distribution) and lower numbers typically map onto worse scores. Therefore a score of 4 indicates a score worse than average.
A test designed to yield information about whether or not a student has mastered the ability to multiply two-digit numbers to a specified level would be referred to as:
(a) Norm-referenced.
(b) Criterion-referenced.
(c) Standardised.
(d) All of the above.
The answer was b. See Lecture 2. This test is measuring whether someone has reached some absolute level of performance - not a given level of performance relative to other people. This means it is criterion-referenced not norm-referenced.
Statement 1: A seven-year-old boy completes a test of reading comprehension and his raw score is converted into a z score of +1.68 compared with other children his own age (higher score = better comprehension). This means he is performing within the middle 68% of children (assuming a normal distribution).
Statement 2: A six-year-old girl completes a test of reading comprehension and her raw score is converted into a z score of +2 compared with other children her own age (higher score = better comprehension). This means her T score on this test would be 70.
(a) Both statements are true.
(b) Statement 1 true; Statement 2 false.
(c) Statement 1 false; Statement 2 true.
(d) Both statements are false.
The answer was c. Note that only the most rudimentary calculation is needed for this question. All you see to know is the mean and SD of a z score and a T score – and that about two thirds of people fit within plus or minus one SD. For Statement 1, it’s saying that he’s within the middle two thirds of the population – i.e. somewhere between -1 and +1 SD from the mean. If his z score is over 1 (remembering z scores are in standard deviation units, and a mean of 0), this can’t be true. For it to be true, his z score would have to be between -1 and +1. For the second statement, a z score of +2 means she is 2 standard deviations above the mean. Given a T score has a mean of 50 and a SD of 10, this means her T score will be 50 + 10 + 10 = 70.
Statement 1: In psychology, raw scores must always be converted into standard scores for ease of interpretation.
Statement 2: If a blood test used to diagnose a particular disease can consistently produce the same diagnosis across multiple patients, then we would consider the test to be valid.
Both statements are true.
Statement 1 true; Statement 2 false.
Statement 1 false; Statement 2 true.
Both statements false.
The answer was d. See Lecture 1. Statement 1 is false: it’s not always necessary to convert raw scores into standardized scores, for example when the raw scores are already in an interpretable form (e.g. reaction times). Statement 2 is false: the ability to produce a CONSISTENT reading indicates the test has RELIABILITY but not necessarily VALIDITY (i.e. just because it is consistent doesn’t mean it is necessarily giving you the correct reading)
A man completes an intelligence test and his raw score is converted into a z score of –2. If his raw score were instead converted into an IQ score, what would it be?
Selected Answer:
(a) 115.
(b) 70.
(c) 80.
(d) 85.
The answer was b. See Lecture 2. IQ scores have a mean of 100 and a SD of 15. Therefore a z score of -2 (2 SDs below the mean) would equate to an IQ score of 100 minus (15 x 2) = 70.
Statement 1: If someone has a positive z score on some measure then we can convert this into a percentile rank by referring to the column marked “smaller portion” on a typical standard normal distribution table.
Statement 2: There will be more people in the 60% to 70% percentile rank range than in the 20% to 30% percentile rank range (assuming a normal distribution).
Selected Answer:
Incorrect
(a) Both statements are true.
(b) Statement 1 true; Statement 2 false.
(c) Statement 1 false; Statement 2 true.
(d) Both statements are false.
The answer was d. See Lecture 2. Statement 1 is false: if the z score is positive, you’d need to refer to the “larger portion” column (the percentile rank MUST be greater than 50 if the z score is positive). Statement 2 is false: there would be the same number of people in each of these bands (i.e. 10% of the sample in each case).
