Stats/Psych Research Chapter 3
bell-shaped curve
Also referred to as a normal distribution or normal curve, a bell-shaped curve is a perfect mesokurtic curve where the mean, median, and mode are equal.
cumulative percentage curve
a graph that consists of a series of connected dots above the upper real limits of each possible class interval (height of the dots corresponds to cumulative percentage)
bar graph
a bar is drawn for each category, where the height of the bar represents the frequency or number of members of that category
U-shaped curve
a curve that results when the frequencies of the values at the extremes of the scale are higher than the frequency of the values in the middle
exploratory data analysis
employs easy-to-construct diagrams that are quite useful in summarizing and describing sample data
A bell shaped curve is an example of a skewed distribution.
false
A histogram is like a bar graph except with a histogram the bars don't touch each other.
false
All frequency distributions should be of grouped scores.
false
The vertical axis, i.e., the Y axis of a graph, is called the abscissa.
false
When constructing frequency distributions there must be 12 class intervals
false
skewed curve
if a curve is not symmetrical
symmetrical curve
if when folded in half the two sides coincide
cumulative frequency distribution
indicates the number of scores that fall below the upper real limit of each interval
cumulative percentage distribution
indicates the percentage of scores that fall below the upper real limit of each interval
relative frequency distribution
indicates the proportion of the total number of scores that occurs in each interval
frequency distribution of grouped scores
individual scores are grouped into class intervals
negatively skewed curve
most of the scores occur at the higher values of the horizontal axis and the curve tails off toward the lower end
positively skewed curve
most of the scores occur at the lower values of the horizontal axis and the curve tails off toward the higher end
frequency distribution
presents the score values and their frequency of occurrence
J-shaped curve
the curve of the exponential growth model when graphed
X axis (abscissa)
the horizontal axis of a graph
percentile rank
the percentage of scores with values lower that the score in question
percentile point
the value on the measurement scale below which a specified percentage of the scores in the distribution fall
Y axis (ordinate)
the vertical axis on a graph
stem and leaf diagrams
they are a simple alternative to the histogram and are most useful for summarizing and describing data when the data set includes less than 100 scores
A "U" shaped distribution would be an example of a symmetrical distribution.
true
A frequency distribution presents the score values and their frequency of occurrence.
true
A stem and leaf diagram contains more information than a histogram
true
If a curve is negatively skewed, most of the scores occur at the higher values and the curve tails off toward the lower end of the horizontal axis.
true
In grouping scores, the wider the intervals, the more information that is lost.
true
One reason for constructing frequency distributions is to be able to visualize the shape of the distribution
true
The percentile rank of a score is equal to the percentage of scores in the distribution that fall below the score in question
true
histogram
used to represent frequency distributions composed of interval or ratio data
frequency polygon
used to represent interval or ratio data
