Research methods and data analysis 2 exam
university of iowa quistions (with complete
solutions and verified answers)
Variance ...ANSWER...descriptive statistic closely related to the standard deviation - it's
the standard deviation squared
Standard Deviation ...ANSWER...descriptive statistic that gives a measure of how much
variation there is in that set of data, around its mean
Calculation for Variance & SD ...ANSWER...1.Calculate the mean of the set of data
2.For each data value, calculate its difference from the mean (deviation from the mean)
3.Square that deviation 4.Add up all the squared deviations •this is called the Sum of
Squares 5.Adjust for the number of data values in the set of data •divide the Sum of
Squares by a number that is based on the number of data values in the set 6.The above
steps give us the Variance of the set of data 7.If we take the square root of this, we get
the Standard Deviation of the set of data
z-score ...ANSWER...A unit-free, standardized score that indicates how many standard
deviations a score is above or below the mean of its distribution.
Standard Error Of Mean ...ANSWER...A rough measure of the average amount by
which sample means deviate from the mean of the sampling distribution or from the
population mean
Sampling Distribution of the Mean ...ANSWER...probability distribution of means for all
possible random samples of a given size from some population.
Central Limit Therom ...ANSWER...Regardless of the population shape, the sampling
distribution of the mean approximates a normal curve if the same size is sufficiently
large.
Population ...ANSWER...•the entire group of things of interest to us •e.g., all 1st graders
in Iowa (let's assume there are 5,00
university of iowa quistions (with complete
solutions and verified answers)
Variance ...ANSWER...descriptive statistic closely related to the standard deviation - it's
the standard deviation squared
Standard Deviation ...ANSWER...descriptive statistic that gives a measure of how much
variation there is in that set of data, around its mean
Calculation for Variance & SD ...ANSWER...1.Calculate the mean of the set of data
2.For each data value, calculate its difference from the mean (deviation from the mean)
3.Square that deviation 4.Add up all the squared deviations •this is called the Sum of
Squares 5.Adjust for the number of data values in the set of data •divide the Sum of
Squares by a number that is based on the number of data values in the set 6.The above
steps give us the Variance of the set of data 7.If we take the square root of this, we get
the Standard Deviation of the set of data
z-score ...ANSWER...A unit-free, standardized score that indicates how many standard
deviations a score is above or below the mean of its distribution.
Standard Error Of Mean ...ANSWER...A rough measure of the average amount by
which sample means deviate from the mean of the sampling distribution or from the
population mean
Sampling Distribution of the Mean ...ANSWER...probability distribution of means for all
possible random samples of a given size from some population.
Central Limit Therom ...ANSWER...Regardless of the population shape, the sampling
distribution of the mean approximates a normal curve if the same size is sufficiently
large.
Population ...ANSWER...•the entire group of things of interest to us •e.g., all 1st graders
in Iowa (let's assume there are 5,00
