Practice Questions from Chapter 1&2 Flashcards
For the interval 1.75-1.99 (where scores are rounded to the nearest hundreth, the interval width is
0.25
For the interval 1.75-1.99 the lower real limit is
1.745
For the interval 1.75-1.99 and the upper real limit is
1.995
For the interval 60-70, where scores are rounded to the nearest ten, the interval width is
11
For the interval 60-70 the lower real limit is
55
For the interval 60-70 and the upper real limit is
75
A researcher collects information on the height of every single US president to look for a correlation between height and success as president. In this case, presidents would be
Population
The purpose of descriptive statistics is to
organize and summarize observations so that they are easier to understand
To say that a score of 120 is 20% higher than a score of 100, is appropriate for
Ratio scale
You collected data from a sample of 100 teenagers on the number of minutes per day that they spend on social media. In order to depict your results graphically, your best option is to use
histogram
Frequency distributions can be reported as
Raw frequencies, proportions, cumulative frequencies
Relative frequency distributions can be useful when
you want to compare two samples that are of different sizes
If a frequency distribution has class intervals of 54-57, 58-61 and 62-65, the interval width (i) is
4
If a frequency distribution has class intervals of 54-57, 58-61 and 62-65, the real limits of that last class interval are
61.5-65.5
If I want to describe the ethnicity of students in my classroom, the best measure of central tendency would be
The mode
When computing the variance, why do we square every deviation score?
In order to keep the scores from summing up to 0
When a distribution is very skewed, the most accurate measure of variability will be
Semi-interquartile range
Imagine a distribution of six scores. What follows are the deviation scores for five of those scores (that is, how each score deviates from the mean): -7, -4, +1, +3, and +5. What is the deviation score of the last number?
+2 (since they must add up to zero)
Converting a score in your distribution into z scores allows one to
determine the distance between that score and the mean of the distribution in a standard metric
A positive skew may have a tail that indicates extreme scores ________ the center of the distribution.
Above
A negative skew may have a tail that indicates extreme scores ________ the center of the distribution.
Below
A grouped frequency table is most useful when….
Data vary over a large range of continuous values
A ________ is a structured presentation of data based on frequencies of classes rather than frequencies of specific values.
Grouped frequency table
