Stats Quiz #11 Z-Scores and Normal Distribution

For any z distribution of normally distributed scores, P50 is always equal to zero.

true

In a normal curve, the area contained between the mean and a score that is 2.30 standard deviations above the mean is 0.4893 of the total area.

true

The area beyond a z score of -1.12 is the same as the area beyond a z score of 1.12.

true

The area under the normal curve represents the percentage of scores contained within the area.

true

The z distribution takes on the same shape as the raw scores.

true

z scores allow comparison of variables that are measured on different scales.

true

In a normal curve, the inflection points occur at _________.

u+1o

The z score and the z distribution are the same thing.

False

A testing bureau reports that the mean for the population of Graduate Record Exam (GRE) scores is 500 with a standard deviation of 90. The scores are normally distributed. The proportion of scores that lie above 650 is _________.

.0475

The proportion of scores less than z = 0.00 is _________.

.50

An economics test was given and the following sample scores were recorded: Individual ABCDEFGHIJ Score 121271091213898 The z score for individual D is _________.

0

The mean of the z distribution equals _________.

0

In a normal distribution the z score for the mean equals _________. Group of answer choices

0 the z score for the median the z score for the mode Correct answer d. all of these

Given the following set of sample raw scores, X: 1, 3, 4, 6, 8. What is the z transformed value for the raw score of 3

0.52

A testing bureau reports that the mean for the population of Graduate Record Exam (GRE) scores is 500 with a standard deviation of 90. The scores are normally distributed. The proportion of scores that lie between 460 and 600 is _________.

0.5365

A standardized test has a mean of 88 and a standard deviation of 12. What is the score at the 90th percentile? Assume a normal distribution.

103.36

On a test with a population mean of 75 and standard deviation equal to 16, if the scores are normally distributed, what is the percentile rank of a score of 56?

11.70

A stockbroker has kept a daily record of the value of a particular stock over the years and finds that prices of the stock form a normal distribution with a mean of $8.52 with a standard deviation of $2.38.

12.44

A stockbroker has kept a daily record of the value of a particular stock over the years and finds that prices of the stock form a normal distribution with a mean of $8.52 with a standard deviation of $2.38. The percentage of scores that lie between $9.00 and $10.00 is _________.

15.31

An economics test was given and the following sample scores were recorded: Individual ABCDEFGHIJ Score 121271091213898 The standard deviation of the distribution is _________.

2.11

A stockbroker has kept a daily record of the value of a particular stock over the years and finds that prices of the stock form a normal distribution with a mean of $8.52 with a standard deviation of $2.38. What percentage of the distribution lies below $7.42.

32.28

If a population of scores is normally distributed, has a mean of 45 and a standard deviation of 6, the most extreme 5% of the scores lie beyond the score(s) of _________.

56.76 and 33.24

A distribution has a mean of 60.0 and a standard deviation of 4.3. The raw score corresponding to a z score of 0.00 is _________.

60.0

A testing bureau reports that the mean for the population of Graduate Record Exam (GRE) scores is 500 with a standard deviation of 90. The scores are normally distributed.

615.20

On a test with a population mean of 75 and standard deviation equal to 16, if the scores are normally distributed, what percentage of scores fall below a score of 83.8? Group of answer choices

70.88

A testing service has 1000 raw scores. It wants to transform the distribution so that the mean = 10 and the standard deviation = 1. To do so, _________.

Both a and d a.compute the deviation score for each raw score. Divide each deviation score by the standard deviation of the raw scores. Take this result for all scores and add 10 to each one. d. do a z transformation for each raw score and add 10 to each z score.

If the original raw score distribution has a mean that is not equal to zero, the mean of the z transformed scores will not equal zero either.

False

If the original raw score distribution is not normally distributed, the mean of the z transformation scores of the raw data will not equal 0. Group of answer choices

False

In the standard normal curve, 13.59% of the scores will always be contained between the mean

False

It is impossible to have a z score of 23.5.

False

If a distribution of raw scores is negatively skewed, transforming the raw scores into z scores will result in a _________ distribution.

Negatively skewed

Makaela took a Spanish exam; her grade was 79. The distribution was normally shaped with X= 70 and s = 12. Juan took a History exam; his grade was 86. The distribution was normally shaped with X= 80 and s = 8. Which did better on their exam relative to those taking the exam?

Neither, they both did as well as each other.

All standard scores are z scores.

True

The normal curve is a symmetric, bell-shaped curve.

True

A z distribution always is normally shaped.

false

If the raw score distribution is very positively skewed, the standard deviation of the z transformed scores will not equal 1.

false

In a plot of the normal curve, frequency is plotted on the X axis.

false

You have just taken a standardized skills test designed to help you make a career choice. Your math skills score was 63 and your writing skills score was 45. The standardized math distribution is normally distributed, with m = 50, and s = 8. The writing skills score distribution is also normally distributed, with m = 30, and s = 10. Based on this information, as between pursuing a career that requires good math skills or one requiring good writing skills, you should chose _________.

good math skills

The z score corresponding to a raw score of 120 is _________.

impossible to compute from the information given

A z score designates how many standard deviations the raw score is above or below the mean.

true

A z score is a transformed score.

true