Exam 4: Percentiles percentile Ranks standard Scores and the Normal Distribution

In a normal distribution,20% of all scores fall between standard scores of -2 and +2.

You discovered that your Statistics professor never gives out raw scores only standard scores.You are relieved because you saw a "0" on the top of your paper.This means you scored_____.

It is always the case that 50% of the scores in a normal distribution occur above the mean and 50% of the scores occur below the mean.

A psychologist is interested in how well people can remember words that they had previously seen.He gives them a list of 70 words,but does not tell them they will be tested later.One week later the students are given a list of 140 words,and told to choose the ones they had seen the previous week.Below is the grouped distribution of the number of words remembered by the subjects. What is the score at the 90th percentile?

The _____ of the standard score formula represents the number of units the score is above or below the mean.

The mean of a set of standard scores is always equal to 0.

Distinguish between a percentile rank and a percentile.

If you wanted to compare the number of hours you sleep with the national average you would have to convert it into____________________.

What proportion of scores in a normal distribution are between z = -2.62 and z = 1.07

A psychologist is interested in how well people can remember words that they had previously seen.He gives them a list of 70 words,but does not tell them they will be tested later.One week later the students are given a list of 140 words,and told to choose the ones they had seen the previous week.Below is the grouped distribution of the number of words remembered by the subjects. What is the percentile rank of a score of 12?

A standard score or Z-score of zero means____________________.

Given a normal distribution with a mean of 50 and a standard deviation of 2,what is the z score of a raw score of 46?

A raw score of 96 on two separate examinations may have different _____ depending on the mean and standard deviations of each examination.

Professor Hansen wants to eliminate any negative standard scores in his class so he should convert scores into____________________.

The standard deviation of a set of standard scores is always equal to 1.00.

A negative standard score indicates that the _____ was below the mean of the distribution.

One property of normal distributions is that the proportion of scores that occur _____ is the same in all such distributions.

One important use of standard scores is to compare scores on distributions that have different means and standard deviations.

To say that a score has a percentile rank of 80 is simply to state that 80% of the individuals scored at or above that score.

The median corresponds to the _____ percentile.