QM revision for the mid term Flashcards
What is a variable?
A variable is anything that can vary.
What is a data distribution?
A data distribution is a listing of values and responses associated with a particular variable.
What are the characteristics of the nominal level of measurement?
It simply presents the frequency of data, the data cannot be compared, and it is based upon categories that are mutually exclusive and collectively exhaustive.
What are the characteristics of the ordinal level of measurement?
In the ordinal level of measurement, there is a notion of order.
What are statistics?
Statistics is collecting, organizing and evaluating data.
What are the characteristics of the interval level of measurement?
You can compare the values, and they are based upon fixed intervals between the values.
What is a representative sample?
A group from a population to help us learn something from that population (to get a proper representation of a population but it doesn’t always do so because of randomization)
What is a population?
Any group of bits of data that we are interested in learning something about.
What is a sample?
A sample is a portion of the population.
What are descriptive statistics?
Descriptive statistics are used to describe or summarize data distributions. For example, using the mean.
What are inferential statistics?
Inferential statistics are used to make statements about a population, based upon information from a sample. (the average age of a Dawson college student, we use a sample to represent the population)
what is data
information about different variables (age for example) is referred to as data.
what is a central tendency
a central tendency is a way to get an idea about the center of a distribution.
What is a mean
The mean is a measure of central tendency. It is a calculated value given to us after summing all the scores in a distribution and deciding the sum by the number of scores.
2 disadvantages of the mean
It is sensitive to extreme values, and it can sometimes give a meaningless value that isn’t in the distribution.
What is a median
the median is a measure of central tendency, it is the score that cuts the distribution in half. When calculating the median the scores have to be arranged in ascending or descending order.
1 disadvantage of the median and 1 advantage
It can sometimes give a value that isn’t on the distribution if the number of scores is even. It can give you a score that’s in the distribution.
What is the mode
it is a measure of central tendency. It’s the score that appears most frequently in a distribution.
disadvantages of the mode and advantages
if there are a lot of modes all the values are disregarding except the one that appears the most frequently. It always gives us a value in the distribution.
what is meant by dispersion
it is an expression of the extent to which the scores are spread out.
what is a range
it is the highest and lowest score in a distribution
what are the deviations from the mean
it is the values obtained by subtracting the mean from each value in the distribution. and the sum of the deviation will always be equal to 0.
what is the mean deviation
it is a measure of dispersion that uses absolute values. However, it isn’t useful when it comes to more complex mathematical operations.
what is the variance
the variance is a measure of dispersion. and by squaring the deviations from the mean it rules out the possibility of negatives.
what is a standard deviation
it is the square root of the variance
why do we do n-1
to get a higher standard deviation to encompass more scores when we do +- the mean.
