Statistics Chapter 2

For the distribution in the following graph, what is the value of ΣX?

30

For the distribution in the following table, what is the percentile rank for X = 24.5?

90%

For the following distribution of scores, X = 18. X f 4 1 3 2 2 3 1 2

False

For the following distribution, how many people had scores less than X = 19?

10

If a set of scores covers a range of 80 points, the grouped frequency table should use an interval width of 8 points.

True

What scale of measurement was used to measure the scores in the distribution shown in the following graph?

ordinal

For the distribution in the following table, what is the 90th percentile? a. X = 24.5 X c% b. X = 25 30-34 100% c. X = 29 25-29 90% d. X = 29.5 20-24 60% 15-19 20%

25

37. For the distribution in the following table, what is the 50th percentile? a. X = 32 X c% b. X = 35 50-59 100% c. X = 37 40-49 90% d. X = 39 30-39 60% 20-29 20%

32

A researcher surveys a sample of n = 200 college students and asks each person to identify his or her favorite movie from the past year. If the data were organized in a frequency distribution table, the first column would be a list of movies.

False

A set of scores ranges from X = 18 to X= 91. If the scores are put in a grouped frequency distribution table with an interval width of 10 points, the top interval would be 91-100.

False

A set of scores ranges from a low of X = 18 to a high of X = 98. If the scores are put in a grouped frequency distribution table with an interval width of 10 points, the bottom interval should be 10-19.

False

A grouped frequency distribution table does not provide enough information to obtain a complete listing of the original set of scores.

True

For the following distribution of scores, X2 = 92. X f 4 1 3 2 2 3 1 2

True

For the following distribution, seven people have scores greater than X = 14. X f 20-24 2 15-19 5 10-14 4 5-9 1

True

What kind of frequency distribution graph shows the frequencies as bars that are separated by spaces?

a histogram

What kind of frequency distribution graph shows the frequencies as bars, with no space between adjacent bars?

a histogram

What is the shape for the distribution shown in the following graph?

a negatively skewed

The normal distribution is an example of

a smooth curve showing data from a population

For the following distribution of quiz scores, How many individuals had a score of X = 2?

cannot be determined

A researcher records the number of traffic tickets issued in each county along the New York State thruway. If the results are presented in a frequency distribution graph, what kind of graph should be used?

either a histogram or polygon

If a set of exam scores forms a symmetrical distribution, what can you conclude about the students scores?

it is not possible to draw any conclusions about the students score

What term is used to describe the shape of a distribution in which the scores pile up on the left-hand side of the graph and taper off to the right?

normal

For the distribution in the following table, what is the percentile rank for X = 7?

x = 37.5%

If the following scores were placed in a stem and leaf display, how many leaves would be associated with a stem of 6? Scores: 26, 45, 62, 11, 21, 55, 66 64, 55, 46, 38, 41, 27, 29 36, 51, 32, 25, 34, 44, 59

3

In a grouped frequency distribution one interval is listed as 50 59. Assuming that the scores are measuring a continuous variable, what are the real limits of this interval?

49.5-59.5

For the scores shown in the following stem and leaf display, what is the highest score in the distribution?

83

In the following distribution, the scores are grouped into class intervals that are each 5 points wide. X f 20-24 2 15-19 5 10-14 4 5-9 1

True

If the following distribution was shown in a histogram, the bar above the 15-19 interval would reach from _____ to _____.

X = 15.5 to X = 19.5

For the distribution in the following table, what is the percentile rank for X = 8.5?

X = 50%

For the following frequency distribution of exam scores, what is the lowest score on the exam?

X = 70

For the distribution in the following table, what is the 90th percentile

X = 9.5

In a frequency distribution graph, frequencies are presented on the and the scores (categories) are listed on the .

class interval/nominal scale

For the following frequency distribution of quiz scores, how many individuals took the quiz?

n = 15

The students in a psychology class seemed to think that the midterm exam was very easy. If they are correct, what is the most likely shape for the distribution of exam scores?

negatively skewed

What is the total number of scores for the distribution shown in the following table? X f 4 3 3 5 2 4 1 2 l

14

For the following distribution, what is the highest score?

20

For the following distribution of quiz scores, if a score of X = 3 or higher is needed for a passing grade, how many individuals passed?

3

It is customary to list the score categories in a frequency distribution from the highest down to the lowest.

False

There is a total of n = 5 scores in the distribution shown in the following table. X f 5 2 4 8 3 5 2 3 1 2

False

In a distribution with positive skew, scores with the highest frequencies are _____.

normal

A group of quiz scores ranges from 3 to 10, but no student had a score of X = 5. If the scores are put in a frequency distribution table, X = 5 would not be listed in the X column.

True

A grouped frequency distribution table lists one interval as, 20-29. The width of this interval is 9 points

True

For the following distribution of scores, 20% of the individuals have scores of X = 1. X f 5 2 4 8 3 5 2 3 1 2

True

The classrooms in the Psychology department are numbered from 100 to 108. A professor records the number of classes held in each room during the fall semester. If these values are presented in a frequency distribution graph, what kind of graph would be appropriate?

a histogram or a polygon

If a frequency distribution is shown in a bar graph, what scale was used to measure the scores?

a nominal or ordinal

For the following distribution, how many people had scores greater than X = 14?

11

A sample of n = 15 scores ranges from a high of X = 11 to a low of X = 3. If these scores are placed in a frequency distribution table, how many X values will be listed in the first column?

15

For the following frequency distribution of exam scores, how many students had scores lower than X = 80?

2

A skewed distribution typically has _____ tail(s) and a normal distribution has ____ tail(s).

2, 2

For the following distribution, what is the width of each class interval?

4

For the distribution in the following table, what is the percentile rank for X = 32? a. 92% X c% b. 92.5% 30-34 100% c. 95% 25-29 90% d. 97.5% 20-24 60% 15-19 20%

92.5%

In a grouped frequency distribution table, one interval is identified as 30-34. This interval has a width of 5 points.

False

In a grouped frequency distribution table, the top value in each class interval should be a multiple of the interval width.

False

What frequency distribution graph is appropriate for scores measured on a nominal scale?

only a histogram

What is the shape of the distribution for the following set of data? Scores: 1, 2, 3, 3, 4, 4, 4 5, 5, 5, 5, 6

positively skewed

For the distribution in the following table, what is the 50th percentile?

symmetrical