PSYC1111 - Week 6 Test with 100%
Correct Solutions
What is the aim of descriptive statistics? - correct Answer-Summarize and describe the
data in a sample
What is central tendency? What are the 3 measures? - correct Answer-A measure that
determines a single value that represents the entire distribution of scores.
The three measures are mean, median and mode
How is mean calculated/formula of mean - correct Answer-Sum of entire set of scores
divided by the number of scores.
What is an outlier? - correct Answer-An extreme value far enough from other values that
it requires an explanation.
the mean is affected by all data points. T or F? - correct Answer-True, having an outlier
will pull the mean in extreme levels
What is a normal distribution? - correct Answer-when 50% of data falls above the mean
and the other 50% falls below the mean. It is a good measure of central tendency and is
representative of data set.
What does it mean when a distribution is positively skewed? - correct Answer-This is
when there are extremely high values so more than 50% of the data falls below the
mean. This doesn't represent data set very well.
What does it mean when a distribution is negatively skewed? - correct Answer-This is
when there are extremely low values so more than 50% of the data falls above the
mean. This doesn't represent data set very well.
What is the median?
- __% of the scores have values that are ___ than median and __% of the scores have
values that are ___ than median. - correct Answer-Midpoint/central value of a list.
- 50, less, 50, more
In a symmetric, unimodal distribution, mode, median and mean are the ____ values. -
correct Answer-Same
, In a positively skewed, unimodal distribution, what are the positions of mean, mode and
median? - correct Answer-The mean is numerically higher than the median and the
mode since it is dragged in direction of skew towards higher end of scale.
In a negatively skewed, unimodal distribution, what are the positions of mean, mode
and median? - correct Answer-The mean is numerically lower than the median or the
mode since it is dragged in direction of skew towards lower end of scale.
which measures of central tendency should you use for nominal, ordinal, interval and
ratio data? - correct Answer-- nominal: mode
- ordinal: median
- interval: mean and median
- ratio: mean and median
What is variability? - correct Answer-measures how spread out/scattered the scores are
in a distribution
Basic descriptive statistics stem from measures of _____ and measures of _____. -
correct Answer-central tendency, variability.
What is a deviation? - correct Answer-distance from a data point to the mean
What is a variance? How to calculate this? - correct Answer-Average error between the
mean and the observations made. Dividing squared deviation by number of
observations, in other words the mean squared deviation.
What is a problem with variance? How to solve this? - correct Answer-It does not
provide the distance in original scale units, but a measure in units squared. Therefore
we have to transform it by square rooting
it. This gives us standard deviation.
what type of scores/scales are needed to measure a mean? - correct
Answer-interval/ratio scale
What type of scores/scales are needed to measure median? - correct Answer-requires
scores that can be placed in rank order (smallest to largest) and are measured on an
ordinal, interval or ratio scale.
the median is affected by extreme values. T or F? - correct Answer-False, the median is
not affected by extreme values.
How is median calculated? - correct Answer-1. ordering data from smallest to largest.
2. For odd number of data values in distribution, median is the middle value in
distribution.
3. For even number of data values in distribution, divide sum of middle two values by
two.
Correct Solutions
What is the aim of descriptive statistics? - correct Answer-Summarize and describe the
data in a sample
What is central tendency? What are the 3 measures? - correct Answer-A measure that
determines a single value that represents the entire distribution of scores.
The three measures are mean, median and mode
How is mean calculated/formula of mean - correct Answer-Sum of entire set of scores
divided by the number of scores.
What is an outlier? - correct Answer-An extreme value far enough from other values that
it requires an explanation.
the mean is affected by all data points. T or F? - correct Answer-True, having an outlier
will pull the mean in extreme levels
What is a normal distribution? - correct Answer-when 50% of data falls above the mean
and the other 50% falls below the mean. It is a good measure of central tendency and is
representative of data set.
What does it mean when a distribution is positively skewed? - correct Answer-This is
when there are extremely high values so more than 50% of the data falls below the
mean. This doesn't represent data set very well.
What does it mean when a distribution is negatively skewed? - correct Answer-This is
when there are extremely low values so more than 50% of the data falls above the
mean. This doesn't represent data set very well.
What is the median?
- __% of the scores have values that are ___ than median and __% of the scores have
values that are ___ than median. - correct Answer-Midpoint/central value of a list.
- 50, less, 50, more
In a symmetric, unimodal distribution, mode, median and mean are the ____ values. -
correct Answer-Same
, In a positively skewed, unimodal distribution, what are the positions of mean, mode and
median? - correct Answer-The mean is numerically higher than the median and the
mode since it is dragged in direction of skew towards higher end of scale.
In a negatively skewed, unimodal distribution, what are the positions of mean, mode
and median? - correct Answer-The mean is numerically lower than the median or the
mode since it is dragged in direction of skew towards lower end of scale.
which measures of central tendency should you use for nominal, ordinal, interval and
ratio data? - correct Answer-- nominal: mode
- ordinal: median
- interval: mean and median
- ratio: mean and median
What is variability? - correct Answer-measures how spread out/scattered the scores are
in a distribution
Basic descriptive statistics stem from measures of _____ and measures of _____. -
correct Answer-central tendency, variability.
What is a deviation? - correct Answer-distance from a data point to the mean
What is a variance? How to calculate this? - correct Answer-Average error between the
mean and the observations made. Dividing squared deviation by number of
observations, in other words the mean squared deviation.
What is a problem with variance? How to solve this? - correct Answer-It does not
provide the distance in original scale units, but a measure in units squared. Therefore
we have to transform it by square rooting
it. This gives us standard deviation.
what type of scores/scales are needed to measure a mean? - correct
Answer-interval/ratio scale
What type of scores/scales are needed to measure median? - correct Answer-requires
scores that can be placed in rank order (smallest to largest) and are measured on an
ordinal, interval or ratio scale.
the median is affected by extreme values. T or F? - correct Answer-False, the median is
not affected by extreme values.
How is median calculated? - correct Answer-1. ordering data from smallest to largest.
2. For odd number of data values in distribution, median is the middle value in
distribution.
3. For even number of data values in distribution, divide sum of middle two values by
two.
