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Exam 2- ch. 4, 5-9, & 11(Evaluating Descriptive Data)questions n answers
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Exam 2- ch. 4, 5-9, & 11(Evaluating Descriptive Data)questions n answers
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Exam 2- ch. 4, 5-9, & 11(EvaluatingDescriptive Data)questions n answers
ch. 4 - correct answer ✔✔
What is the difference between descriptive and inferential statistics? - correct answer ✔✔-Descriptive
statistics describe the data in a study. They provide an analysis of data that helps describe, show, or
summarize it in a meaningful way such that patterns could emerge from the data.
-Inferential statistics are techniques that allow us to use study samples to make generalizations that
apply to the population.
-Descriptive statistics are used in the calculation of inferential statistics.
-An important element of inferential statistics is "infer"- used when a researcher wants to infer
something about a larger population based on the sample used in the study. They are often divided into
two categories: 1- test of differences (e.g. t-tests and analysis of variance) and 2- tests of relationships
(e.g. correlations and regressions). With inferential statistics, a test is conducted to determine if the
difference or relationship is statistically significant.
Less wordy answer to: What is the difference between descriptive and inferential statistics? - correct
answer ✔✔-Descriptive stats describe the data in a study (an analysis of data that helps us describe,
show or summarize it in a meaningful way)
-Inferential stats are techniques that allow us to use study samples to make generalizations that apply to
the population
o Descriptive stats are used in the calculation of inferential statistics
Define the three main measures of central tendency - correct answer ✔✔-The measure of central
tendency describes the location of the center of a distribution. The three measures of central tendency
are mode, median, and mean.
,-The mode is the score value that occurs most frequently in the distribution. The mode provides
information about the distribution, but it is generally of less use than the other measures of central
tendency. Greatly influenced by chance.
-Median is the score value that divides the distribution into the lower and upper halves of the scores.
This is most useful when distributions are skewed, because it is less sensitive to extreme scores.
-Mean is the same as the average and balances the scores above and below it. Calculated by summing
the scores and dividing the sum by the number of participants. Used most often in research, particularly
when calculating inferential statistics.
Describe how the measures of central tendency are affected by a skewed distribution (Fig 4-2) - correct
answer ✔✔When the distribution is positively skewed, the mode is a lower score than the mean, while
the median falls between the mode and mean.
In a negatively skewed distribution, the mode is a higher score than the mean, and once again the
median falls between the mode and mean.
Define the two main measures of variability? - correct answer ✔✔-Range and standard deviation are the
two main measures of variability.
-Variability refers to the spread of scores in a distribution. Distributions with the same central tendencies
can still be very different because of the variability in the scores. Measures of variability is range and
standard deviation.
-Range is one measure of central tendency that indicates the lowest and highest scores. For example, the
age range of participants could be 18-49.
-The most common measure of variability is standard deviation. Standard deviation is the expression of
the amount of spread in the frequency distribution and the average amount of deviation by which each
individual score varies from the mean. A large standard deviation means there is a high degree of
variability and a small standard deviation means that there is a low degree of variability.
,What are some examples of graphs and figures that are used in descriptive statistics? - correct answer
✔✔Qualitative:
•Frequency distribution- when a graph is used to depict the count
- Frequency tables
•Bar graph
•Pie chart
•Contingency tables
Quantitative:
•Histogram
•Stemplots
•Dotplots
•Scatterplots
•Boxplot
What are the two categories that inferential statistics are often divided into? - correct answer ✔✔1)
tests of differences (e.g., t-tests and analysis of variance)
and
2) tests of relationships (e.g. correlations and regressions)
With inferential statistics, a test is conducted to determine if the difference or relationship is statistically
significant
what are the two primary approaches that are used for statistical inference? - correct answer ✔✔-
confidence intervals: an approach to estimate a population parameter from a sample statistic
-hypothesis testing: an approach to test an assumption about a population parameter from a sample
statistic
, Recognize the inferential statistics that may be used to analyze differences in means. - correct answer
✔✔?? is this answer right??
There are many statistical tests for comparing differences, but the most common difference statistics are
the t-test and analysis of variance (ANOVA). In these tests, the means of the two groups and/or time
periods are compared, while taking into account the standard deviations of the means. If a difference is
found within the sample, an inference is made that a difference would exist within a larger population.
-The t-test is the most basic of inferential difference statistics because it examines the difference
between two groups at a single time point, or one group at two time points.
-When more than two means are compared, an analysis of variance (ANOVA) is the appropriate test.
With a t-test, the t statistic is used. With an ANOVA, an F-test is used to compare means, and the F
statistic is used.
from her voicethread about difference in means
what does difference in means, mean? - correct answer ✔✔Many rehabilitation studies are interested in
differences. intervention studies seek to determine whether there is a difference between the
intervention and control groups, or whether there are differences before and after treatment.
a descriptive study may examine the differences between people with and without a condition.
what is the main purpose of a t-test - correct answer ✔✔examine the differences in means
Look at picture I took from her voicethread
When do you use an ANOVA test - correct answer ✔✔when more than two means are compared
when more than two comparisons are made, follow-up tests are necessary to determine where the
differences lie.
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