Normal Curve and Score Transformations Flashcards

Fill-in-the-blank practice flashcards covering normal curve properties, kurtosis, percentile ranks, and score transformation formulas.

In a normal distribution, the skewness is __________.

zero (i.e., no skew)

In terms of modality, a normal distribution is described as __________.

unimodal

In terms of kurtosis, a normal distribution is classified as __________.

mesokurtic

A distribution with fatter tails, a higher number of outliers, and a kurtosis greater than zero is called __________.

leptokurtic

A distribution with thinner tails, a smaller number of outliers, and a kurtosis less than zero is called __________.

platykurtic

In a normal curve, approximately __________% of scores fall within $\pm 1\,SD$ of the mean.

68.26

In a normal curve, approximately __________% of scores fall within $\pm 2\,SD$ of the mean.

95.44

In a normal curve, approximately __________% of scores fall within $\pm 3\,SD$ of the mean.

99.74

A percentile rank expresses the percentage of scores that fall __________ a specific raw score.

below

In the percentile rank formula $PR = \frac{n_L}{N}(100)$, $n_L$ represents the __________.

number of scores in the distribution lower than score being transformed

Transforming scores to percentiles distorts the underlying measurement scale because percentiles do not form an __________ scale of measurement.

interval

A standard normal distribution of $Z$ scores has a mean of __________ and a standard deviation of __________.

$0$ and $1$

The formula to calculate a $Z$ score from a raw score $X$ is $Z =$ __________.

$$\frac{X - M}{SD}$$

Deviation IQ scores used in Wechsler aptitude scales have a mean of __________ and a standard deviation of __________.

$100$ and $15$

CEEB scores used in educational testing (such as the SAT or GRE) have a mean of __________ and a standard deviation of __________.

$500$ and $100$

Personality tests such as the MMPI-2 use $T$ scores, which have a mean of __________ and a standard deviation of __________.

$50$ and $10$

The generic formula used to transform a $Z$ score into a new score distribution $X'$ is $X' =$ __________.

$$(Z)(SD) + M$$

When rounding standardized scores, $Z$ scores are rounded to the __________ place, while $T$, IQ, and CEEB scores are rounded to __________.

hundredths; whole numbers

In a normal distribution, a score $1\,SD$ above the mean corresponds to an approximate percentile rank of __________.

84

In a normal distribution, a score $2\,SD$ above the mean corresponds to an approximate percentile rank of __________.

98

In a normal distribution, a score $1\,SD$ below the mean corresponds to an approximate percentile rank of __________.

16