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Unit 2: Graphical Representations and Frequency Distribution - Practice Quiz

PSY115 — Statistical Methods For Psychological Research 60 Questions
0 Correct 0 Wrong 60 Left
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1 What is a major advantage of presenting data graphically?

importance of graphical representation of data Easy
A. It replaces the need for data collection
B. It makes patterns easier to see
C. It increases the sample size
D. It removes all errors from data

2 Which feature makes a graph useful for comparing groups?

importance of graphical representation of data Easy
A. A higher response rate
B. A clear visual display
C. A larger research budget
D. A longer questionnaire

3 A graph showing scores across several months is especially useful for identifying what?

importance of graphical representation of data Easy
A. The cause of every score
B. Trends over time
C. The exact research hypothesis
D. The name of each participant

4 Which graph is commonly used to display ungrouped categorical data?

graphical representation of grouped and ungrouped data Easy
A. Frequency polygon
B. Histogram
C. Ogive
D. Bar graph

5 Which graph is most appropriate for continuous grouped data?

graphical representation of grouped and ungrouped data Easy
A. Pictograph
B. Pie chart
C. Simple bar chart
D. Histogram

6 In a histogram, the bars usually touch because the data are:

graphical representation of grouped and ungrouped data Easy
A. Qualitative only
B. Unrelated
C. Nominal
D. Continuous

7 Which graph uses sectors of a circle to show parts of a whole?

graphical representation of grouped and ungrouped data Easy
A. Frequency polygon
B. Pie chart
C. Histogram
D. Stem-and-leaf plot

8 What does frequency mean in a frequency distribution?

frequency distributions Easy
A. The difference between two values
B. The number of times a value occurs
C. The largest value in a set
D. The average value of a set

9 What is the main purpose of a frequency distribution?

frequency distributions Easy
A. To prove a research theory
B. To identify individual participants
C. To calculate only the median
D. To organize data by frequency

10 If the scores are 2, 3, 3, 4, and 4, what is the frequency of the score 3?

frequency distributions Easy
A. 1
B. 2
C. 3
D. 4

11 What is a class interval in a grouped frequency distribution?

frequency distributions Easy
A. A range of values
B. The total number of observations
C. The difference between the mean and median
D. A single participant's score

12 If the frequencies in a distribution are 4, 6, and 5, what is the total frequency?

frequency distributions Easy
A. 20
B. 15
C. 10
D. 9

13 In statistical terminology, a decile divides an ordered data set into how many equal parts?

docile Easy
A. Five parts
B. Ten parts
C. Four parts
D. One hundred parts

14 The fifth decile, , is equivalent to which measure?

docile Easy
A. The mode
B. The variance
C. The median
D. The range

15 Which decile represents approximately the 20th percentile?

docile Easy
A.
B.
C.
D.

16 Quartiles divide an ordered data set into how many equal parts?

quartile Easy
A. Ten parts
B. Four parts
C. Two parts
D. Three parts

17 Which quartile is also called the median?

quartile Easy
A.
B.
C.
D.

18 The first quartile, , represents approximately which percentile?

quartile Easy
A. 10th percentile
B. 25th percentile
C. 75th percentile
D. 50th percentile

19 What does the 80th percentile indicate?

percentile Easy
A. 80% of scores are at or below it
B. It is always the highest score
C. 80% of scores are above it
D. It is the average of all scores

20 A percentile is used to describe the relative position of a score within a:

percentile Easy
A. Questionnaire
B. Distribution
C. Research hypothesis
D. Laboratory instrument

21 A researcher wants to compare anxiety scores for three different therapy groups quickly. Which graphical method is most appropriate?

importance of graphical representation of data Medium
A. A bar graph showing group means
B. A pie chart showing score ranges
C. A frequency polygon showing categories
D. A histogram showing all individual scores

22 A distribution has a few extremely high scores. Which advantage of a graph would help a researcher identify this feature most easily?

importance of graphical representation of data Medium
A. It reveals unusual patterns visually
B. It guarantees that scores are normally distributed
C. It replaces the need for data collection
D. It removes the effect of extreme scores

23 For the ungrouped scores , which graph best displays the frequency of each exact score?

graphical representation of grouped and ungrouped data Medium
A. A pie chart with continuous boundaries
B. A histogram with unequal intervals
C. A frequency polygon with no plotted points
D. A bar graph with separate score values

24 A grouped distribution uses class intervals –, –, and –. Which class boundaries make the intervals continuous?

graphical representation of grouped and ungrouped data Medium
A. –, –, –
B. –, –, –
C. –, –, –
D. –, –, –

25 Which graph is most suitable for showing the shape of a continuous grouped distribution of reaction times?

graphical representation of grouped and ungrouped data Medium
A. A histogram
B. A pie chart
C. A simple bar chart
D. A pictograph

26 The frequencies for four categories are , , , and . What is the cumulative frequency through the third category?

frequency distributions Medium
A.
B.
C.
D.

27 A frequency distribution has class frequencies , , , and . What percentage of observations lies in the third class?

frequency distributions Medium
A.
B.
C.
D.

28 A distribution has class intervals –, –, and – with frequencies , , and . What is the frequency density of the second class?

frequency distributions Medium
A.
B.
C.
D.

29 A researcher records the number of correct responses made by participants: . What is the modal score?

frequency distributions Medium
A.
B.
C.
D.

30 In a frequency distribution, the cumulative frequencies are , , , and . How many observations are in the third class?

frequency distributions Medium
A.
B.
C.
D.

31 The of a test-score distribution is best interpreted as the score below which approximately what percentage of observations fall?

docile Medium
A.
B.
C.
D.

32 For the ordered scores , using the position formula , where is located?

docile Medium
A. At the th position
B. At the th position
C. At the th position
D. At the th position

33 A student's score is at in a distribution. Which statement is most accurate?

docile Medium
A. About scored lower
B. About scored lower
C. About scored higher
D. About scored lower

34 For the ordered scores , using the median-of-halves method, what is ?

quartile Medium
A.
B.
C.
D.

35 If and , what is the interquartile range?

quartile Medium
A.
B.
C.
D.

36 A distribution has , median , and . Which conclusion is supported by these values?

quartile Medium
A. The upper half has greater spread
B. Both halves have equal spread
C. The lower half has greater spread
D. The total range is

37 In a class of students, a score equal to indicates that approximately how many students scored at or below that value?

quartile Medium
A. 35 students
B. 30 students
C. 10 students
D. 20 students

38 A score is at the in a psychological assessment. What does this mean?

percentile Medium
A. The score exceeds about 65\% of scores
B. The score has a frequency of 65
C. The score is 65\% of the maximum
D. The score is 65 points above average

39 For the ordered scores , using the position formula , what is the position of ?

percentile Medium
A. At the th position
B. At the th position
C. At the th position
D. At the th position

40 A researcher wants to identify participants whose scores fall in the highest of the distribution. Which cutoff should be used?

percentile Medium
A.
B.
C.
D.

41 A researcher compares anxiety scores from two samples. Sample A has a mean of 40 and SD of 4, while Sample B has a mean of 60 and SD of 12. Which graphical strategy best prevents a misleading visual comparison of variability?

importance of graphical representation of data Hard
A. Use identical axes and plot raw scores
B. Use standardized scores on a common axis
C. Use separate axes optimized for each sample
D. Use a pie chart for both samples

42 A report uses a truncated bar-chart axis beginning at 95 to display mean scores of 96, 98, and 100. What is the principal inferential danger?

importance of graphical representation of data Hard
A. The bars may exaggerate small absolute differences
B. The graph necessarily conceals the sample size
C. The means become mathematically impossible to compare
D. The chart cannot display categorical variables

43 A distribution has a strong positive skew and one extreme score. Which pair of summaries is most appropriate for a graph intended to communicate the typical participant and dispersion robustly?

importance of graphical representation of data Hard
A. Median and interquartile range
B. Mode and variance
C. Minimum and maximum only
D. Mean and standard deviation

44 Reaction times are recorded as 241, 242, 243, and 244 ms, with no repeated values. Which display is most suitable for preserving the exact observations while revealing concentration?

graphical representation of grouped and ungrouped data Hard
A. A histogram with four equal-width bins
B. A bar chart of nominal categories
C. A stem-and-leaf plot
D. A pie chart with four sectors

45 Two histograms represent the same continuous scores, but one uses class widths of 5 and the other uses widths of 10. Which comparison is valid?

graphical representation of grouped and ungrouped data Hard
A. Compare the number of plotted rectangles
B. Compare frequency densities across classes
C. Compare only the tallest class
D. Compare raw bar heights directly

46 A grouped frequency table has classes , , and . For a continuous histogram, which class boundaries are correct if measurements were rounded to the nearest whole unit?

graphical representation of grouped and ungrouped data Hard
A. , , and
B. , , and
C. , , and
D. , , and

47 A frequency polygon is constructed from classes , , and . At which values should the class-frequency points be plotted?

graphical representation of grouped and ungrouped data Hard
A. At 4.5, 14.5, and 24.5
B. At 9, 19, and 29
C. At 0, 10, and 20
D. At 5, 15, and 25

48 A frequency distribution has class frequencies and . What is the cumulative frequency immediately after the fourth class?

frequency distributions Hard
A.
B.
C.
D.

49 A sample of participants is summarized by frequencies and . What percentage lies in the third or fourth class combined?

frequency distributions Hard
A.
B.
C.
D.

50 A grouped distribution has classes , , and with frequencies , , and . Using class midpoints, what is the estimated mean?

frequency distributions Hard
A.
B.
C.
D.

51 A grouped distribution has unequal intervals , , and , with frequencies , , and . Which histogram heights are proportional to frequency density?

frequency distributions Hard
A.
B.
C.
D.

52 For a distribution with , the 7th decile is located at which position under the convention at ?

docile Hard
A. The 70th observation
B. The 7th observation
C. The 140th observation
D. The 170th observation

53 The ordered scores are . Using the position formula , what is the 6th decile?

docile Hard
A.
B.
C.
D.

54 A grouped distribution has class intervals , , , and , with frequencies and . Estimate the 6th decile using continuous boundaries.

docile Hard
A.
B.
C.
D.

55 For the ordered data , using the median-of-halves method, what is the interquartile range?

quartile Hard
A.
B.
C.
D.

56 A distribution has , median , and . Which conclusion is best supported by these quartiles?

quartile Hard
A. The upper half has greater spread
B. The lower half has greater spread
C. The distribution must be symmetric
D. Both halves have identical spread

57 A boxplot has minimum , , median , , and maximum . Which feature is most clearly indicated?

quartile Hard
A. No possible outliers under any rule
B. Perfect symmetry around the median
C. A negative skew with a longer lower tail
D. A positive skew with a longer upper tail

58 A participant's score is at the 85th percentile. Which interpretation is correct?

percentile Hard
A. The participant is 85 points above the mean
B. The participant's score is 85% of the maximum
C. The participant answered 85% of items correctly
D. The participant scored higher than about 85% of cases

59 In a class of students, a score has percentile-rank position . Between which ordered observations does the 75th percentile fall?

percentile Hard
A. Exactly at the 30th observation
B. Between the 30th and 31st observations
C. Between the 29th and 30th observations
D. Between the 28th and 29th observations

60 A grouped distribution has classes , , , and , with frequencies and . Estimate the 75th percentile using continuous boundaries.

percentile Hard
A.
B.
C.
D.
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