Stats Practice Quiz, Chapter 2

A graphical display in the shape of a circle that is used to summarize the relative percent of discrete and categorical data into sectors is called a:

a. bar chart b. flow chart c. pie chart d. frequency (c)

If a researcher constructs a simple frequency distribution with a recording of 8 in the first interval, 12 in the second interval, 4 in the third interval, 6 in the fourth interval, and 10 in the fifth and final interval, then how many scores in total were recorded in this study?

a. 14 scores b. 15 scores c. 40 scores d. not enough information (c)

If the smallest score in a distribution is 10 and the largest is 32, then what is the real range for these data?

a. 20 b. 21 c. 22 d. 23 (d)

As a general rule, when the number of intervals needed to summarize a data set is smaller than ______, we can leave the data ungrouped.

a. 5 b. 10 c. 15 d. 20 (a)

If the smallest score in a distribution is 12 in the largest 71, what is the interval width if we create 6 intervals?

a. 6 b. 9.83 c. 10 d. 12 (c)

State the percentile point of the 50th percentile for a distribution with a cumulative percent distribution of 12%, 40%, 50%, 80%, 100% at each of the following intervals: 0-2, 3-5, 6-8, 9-11, and 12-14, respectively.

a. 7 b. 8 c. 9 d. 10 (b)

The lower boundaries in a frequency distribution of response times (in seconds) during a training exercise are 65, 76, 87, and 98. What is the interval width for this frequency distribution?

a. 9 b. 10 c. 11 d. 12 (c)

Each of the following is a rule for constructing a histogram, except:

a. a vertical rectangle represents each interval, and the height of the rectangle equals to frequency recorded for each interval b. the base of each rectangle begins and ends at the upper and lower boundaries of each interval c. each rectangle touches adjacent angles at the boundaries of each interval d. frequencies are plotted at the midpoints of each interval, and the line connects each plot (d)

A researcher measures the number of votes submitted for each of three candidates. What type of graph was used to summarize these data? Is it appropriate?

a. bar chart; yes, because the data are continuous b. bar chart; yes, because the data are categorical c. bar chart; no, because the data are categorical d. histogram; yes, because the data are continuous (b)

How do you convert a relative frequency to a relative percent distribution?

a. divide each frequency by the total number of observations recorded b. sum the frequencies in each interval, then divide by the number of intervals c. no calculation is needed; a relative frequency is the same as a relative percent d. multiply the relative frequency by 100 at each interval (d)

Which of the following is not a step to identify the percentile point in a frequency distribution?

a. find frequency of scores in one interval and divide by the total frequency b. identify the interval within which a specified percentile point falls c. identify the real range for the interval identified d. find the position of the percentile point within the interval (a)

Which of the following would be most appropriate for summarizing the relative percent in each category for a discrete variable?

a. frequency polygon b. histogram c. ogive d. pie chart (d)

It is necessary to create intervals for a simple frequency distribution with what type of data?

a. grouped data b. ungrouped data c. categorical data d. nominal scale data (a)

A researcher measures the distance (in miles) that students travel during a holiday season. What type of graph was used to summarize these data? Is it appropriate?

a. histogram; yes, because the data are continuous b. histogram; yes, because the data are discrete c. histogram; no, because the data are continuous d. bar chart; yes, because the data are discrete (a)

A relative percent distribution is often used instead of a relative frequency distribution because:

a. it is more appropriate b. it is more accurate c. it is more meaningful d. most readers find it easier to understand percentages than decimals (d)

A frequency polygon is a dot-and-line graph where the dot is the ______ of each interval, the line connects each dot.

a. lower boundary b. midpoint c. upper boundary (b)

An ogive is used to summarize what type of frequency distribution?

a. relative percent b. percentile rank c. relative frequency d. cumulative percent (d)

A ______ is a cumulative percent summary in which the ranks indicate the percent of scores at or below a given value.

a. relative point b. percentile rank c. relative frequency d. cumulative frequency (b)

A ______ frequency distribution is often used for larger data sets where the number of frequencies in each interval could be in the thousands or millions.

a. simple b. cumulative c. relative d. differential (c)

When we sum the frequencies across the series of intervals, the summary is called a:

a. simple frequency distribution b. cumulative frequency distribution c. relative frequency distribution d. cumulative percent distribution (b)

A bar chart is similar to a histogram, except that in a bar chart, each rectangle ______ the adjacent rectangles at the boundaries of each interval.

a. touches b. does not touch c. overlaps with (b)

Summarizing ungrouped data is especially practical for data sets with only a few different scores and for qualitative or categorical variables.

a. true b. false (a)

A researcher measures the following scores: 0, 2, 2, 2, 2, 2, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, and 0. Should these data be grouped?

a. yes, because so many scores were measured b. yes, because the range of values is small c. no, because the data are categorical d. no, because the number of different scores is small (d)