Statistics Week 2

A bar graph is constructed so that adjacent bars touch. T OR F

False

A distribution of scores has a mean of 52, a median of 54, and a mode of 56. Based on this information, it appears that the distribution is symmetrical. T OR F

False

A group of quiz scores ranges from 3 to 10, but no student had a score of X = 7. If the scores are put in a frequency distribution table, X = 7 would not be listed in the X column. T OR F

False

A sample of n = 6 scores has ΣX = 48. This sample has a mean of M = 6. T OR F

False

A sample with a mean of M = 20 has ΣX = 120. There are n = 5 scores in this sample. T OR F

False

A set of quiz scores ranges from a low of X = 58 to a high of X = 93. If the scores are place in a grouped frequency distribution table with an interval width of 5 points, the bottom interval should be 55-60. T OR F

False

A set of scores ranges from X = 13 to X = 73. If the scores were put in a grouped frequency distribution table with an interval width of 10 points, the top interval would be 73-82. T OR F

False

A set of scores ranging from a high of 41 to a low of 5 is organized into a grouped frequency distribution table using an interval width of 5 points. If the distribution is shown in a graph, then a bar graph should be used. T OR F

False

A sports historian records the number of times that the Minnesota Twins finished 1st, 2nd, 3rd, 4th, or 5th in their division for each of the last 20 years. If the results are presented in a frequency distribution graph, then a histogram should be used. T OR F

False

A student takes a 10-point quiz each week in statistics class. If the student's quiz scores for the first three weeks are 10, 8, and 8, then the mean score is M = 9. T OR F

False

For a distribution that measures a discrete variable with an even number of scores, the median is usually just as valid as the mode to use as a measure of central tendency. T OR F

False

For the following distribution of scores that come from a continuous variable, the upper real limit for the interval that includes X = 2 is 2. T OR F X f 5 3 4 2 3 5 2 1 1 3

False

For the following frequency distribution of quiz scores, 10% of students have scores of X = 2. T OR F X f 5 4 4 4 3 6 2 4 1 2

False

If a positively skewed distribution has a mean of 40, then the median and the mode are probably both greater than 40. T OR F

False

If a sample has an even number of scores, at least one individual will have a score exactly equal to the median. T OR F

False

If a set of scores covers a range of 70 points, then the grouped frequency table for the scores should use an interval width of 7 points. T OR F

False

In a negatively skewed distribution, scores either pile up on the left side of the distribution or pile up on the right side of the distribution. T OR F

False

It is possible for a distribution to have more than one median. T OR F

False

The major mode in the distribution of scores below is X = 5. T OR F

False

The median is considered to be the "balance point" for a distribution because it is the score for which the total distance between scores below the median and the median is identical to the total distance between scores above the median and the median. T OR F

False

A distribution of scores on a driver's license test forms is normally shaped. This is an example of a symmetrical distribution. T OR F

True

A sample has a mean of M = 30. If a new score of X = 45 is added to the sample, then the sample mean would increase. T OR F

True

A sample has n = 6 scores: 1, 1, 3, 4, 6, and 8. The median for this sample is 3.5. T OR F

True

For the following distribution of scores, 80% of individuals scored either a 2 or greater than 2. T OR F X f 5 4 4 3 3 6 2 3 1 4

True

For the scores in the following frequency distribution table, the mean is M = 3. T OR F X f 5. 3 4 1 3 3 2 3 1 2

True

In August in Florida, the daily high temperatures are typically high with only a few relatively cool days. A frequency distribution graph showing daily average temperatures in Florida for August would probably form a negatively skewed distribution. T OR F

True

In a grouped frequency distribution table, scores range from X = 15 to X = 52 with class interval widths of 5. The bottom class interval should be 15-19.. T OR F

True

In a grouped frequency distribution table, the bottom value in each class interval should be a multiple of the interval width. T OR F

True

In a symmetrical distribution, the right side of the graph is a mirror image of the left side of the graph. T OR F

True

In general, more information is lost in a grouped frequency distribution table that has class intervals with a width of 10 than a grouped frequency distribution table that has class intervals with a width of 5. T OR F

True

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

True

It is possible for the value of the median to be greater than the value of the mode. T OR F

True

It is possible to have a distribution of scores where no individual has a score exactly equal to the mean. T OR F

True

Regardless of whether a distribution of scores that is symmetrically shaped has one mode or two modes, the mean value tends to be similar to the median value. T OR F

True

Skewed distributions, open-ended distributions, or discrete variables are situations for which the mean cannot be calculated or for which the mean may not be the best measure of central tendency to utilize. T OR F

True

The classrooms in a Psychology department are numbered from 200 to 210. The department chair records the number of classes held in each room during the spring semester. If the results needed to be presented in a frequency distribution graph, the professor should use a bar graph. T OR F

True

The median is the best measure of central tendency to use in order to describe the distribution of scores below pertaining to the average daily coffee consumption of a sample of individuals. T OR F Daily Cups of Coffee Consumed (X) f 4 or more 2 3 2 2 1 1 3 0 3

True

The median is the value in a distribution of scores that separates the lowest 50% of scores from the highest 50% of scores. T OR F

True

This grouped frequency distribution appropriately adheres to the guidelines pertaining to creating grouped frequency distribution tables. T OR F X f 25-29 1 20-24 6 15-19 5 10-14 8 5-9 3 0-4 2

True

A population of N=6 scores has EX=42. What is the population

U=7

Consider the distribution of exam scores for the first exam within a college course. If the set of exam forms is symmetrical distribution, what can be concluded about the student's scores? a) a substantial number of students had high scores b)About an equal number of students had relatively high and relatively low scores c)most had low scores

b)

A professor recorded the academic major for each student in an introductory psychology class. If the data are presented in a frequency distribution graph, what type of graph should be used? a)histogram b)polygon c)histogram or polygon d)bar graph

d)bar graph

What is the median of the following scores: 1,3,9,10,22

9

A grouped frequency distribution table lists one interval as 15-20. The width of this interval is 5 points. T OR F

False

A professor records the number of students who are absent each day for the semester. Given the scale of measurement used when measuring this variable, a bar graph should be used to show the frequency distribution. T OR F

False

A researcher records the list of finishes (e.g., 1st, 2nd, 3rd, 4th) for a track team throughout their season. The mean is the best measure of central tendency to report in this circumstance to describe the most typical finish for this track team. T OR F

False

A sample of n = 6 scores has a mean of M = 10. After one score is removed from the sample, the mean is calculated to be M = 8. The removed score must have a value less than 10. T OR F

False

For a severely skewed distribution, the mean often provides a better measure of central tendency than the median or the mode. T OR F

False

A sample of n = 8 scores has a mean of M = 16. For this sample, ΣX = 128. T OR F

True

Consider that a sample of individuals each report how many siblings they have, and this data is then put into a grouped frequency distribution table. This grouped frequency distribution table will not provide enough information to obtain a complete listing of the original responses of individuals. T OR F

True

For a negatively skewed distribution, the mode is usually larger than either the median or the mean. T OR F

True

For any distribution of sample scores, at least one individual will have a score exactly equal to the mode. T OR F

True

For the distribution shown in the table below, 60% of scores are less than X = 3. T OR F X f 5 2 4 5 3 3 2 8 1 7

True

For a positively skewed distribution with u = 30, what is the most likely location for the median? A. Equal to 30 B. Greater than 30 C. Less than 30 D. Cannot be determined from the information provided

c)Less than 30

For a negatively skewed distribution with a mode of X = 25, and a mean of M=20, the median is probably? a)greater than 25 b)less than 20 c)between 20 and 25 d) cant do it

c)between 20 and 25

A set of scores ranges from a high of X = 18 to a low of X = 5. If these scores were put in a frequency distribution table with an interval width of 2 points, which of the following would be the top interval in the table? a) 5-6 b) 18-19 c) 4-5 d) 17-18

d)

A distribution of scores is positively skewed. Which is the most probable order, from smallest to largest, for the three measures of central tendency?

mode, median, mean

The following table shows a frequency distribution of exam scores. How many students had scores less than x=60 x f 70-74 3 65-69 4 60-64 8 55-59 2 50-54 1 45-49 1

4

Which types of graphs are used for data from an interval scale?

Histograms and polygons

In a negatively skewed distribution of exam scores, Tom scored at the mean, Mary at the median and Jane at the mode. Who was highest?

Jane

No space is left between adjacent bars in a histogram. T OR F

True

Which of the following statements must must be false regarding a distribution of scores? a)no individual has a score equal to the mode b)all of these are false c)no individuals has a score exactly equal to the mean d)no individual has a score exactly to the median.

a)no individual has a score exactly equal to the mode

A researcher surveys a sample of n=10 adults and asks them to indicate their favourite day of the week. If the data were organized in a frequency distribution table, what would be included in the first column? a)list of frequencies b)list of average c)list of students d)list of days of the week

d)list of days of the week

For a perfectly symmetrical distribution with a U of 30, what is the value of the median?

equal to 30

what is the shape of the distribution for the following set of scores: 25,26,24,25,3,7,6,15,10,25,24,26

negatively skewed