Chapter 1
A research study reports that alcohol consumption is significantly higher for students at a state university than for students at a religious college (Wells, 2010). Is this study an example of an experiment? Why?
No, there is no control group
The minimum sample size for a good frequency distribution
n = 30
True or False:
When the Mean, Median, and Mode are all aligned, it indicates that there is no skew
True
Deviation can best be defined as __
The distance from the mean
What do z scores measure
How many standard deviations a score is from the mean
A researcher developing a new medication to help people sleep longer and wants to see how well it affects school children. These are the independent and dependent variables he will measure
Independent: Taking the sleep aid
Dependent: Hours slept
A symmetrical and bell-curve shaped distribution is often considered a(n)
Normal Distribution
How many scores are found to the left of the median?
Half
Standard Deviation is found by doing what to variance
Taking the square root
99.7% of the time, a z score will never exceed this value
3
The number of grounds keepers in Utah and the number of Bachelors degrees awarded in Psychology had a correlation coefficient of 0.99. The example helps illustrate correlational studies are less informative than controlled experiments because of this reasoning
Correlation does not show causation
An outlier far to the left of the mean will cause a distribution to be ___
Negatively Skewed
When considering central tendency on a graphed frequency distribution, the peak of the bell curve always indicates the __ of a data set
x̄ and μ are both symbols for mean. What differentiates them?
μ is for population mean while x̄ is for sample mean
A distribution made up of z scores is known as a(n) ___
Standard Distribution
A researcher developing a new medication to help people sleep longer and wants to see how well it affects school children. This is the alternate and null hypothesis the researcher should use
H0 Children who take the sleep aid will sleep the same amount of hours or less as children who do not take the sleep aid
H1 Children who take the sleep aid will sleep more hours than children who do not take the sleep aid
A frequency distribution with two predominant "peaks" is known as a(n) ___
Bimodal Distribution
A negatively skewed distribution will have a mean that is what in comparison to the median?
Less than
To calculate variance you divide ___ by ___
Degrees of Freedom (df)
True or False
A Standardized Sistribution must always have a mean of 0
False (e.g. IQ Tests: mean is 100)
The strongest and weakest forms of evidence in statistics
Meta Analysis
Qualitative Studies
True or False:
Degrees Kelvin is an example of interval data while Degrees Celsius is an example of Ratio
False: Ratio data includes a meaningful null value
Kelvin = Ratio as absolute zero exists
Celcius = Interval because zero is the freezing point of water, not a true lack of temperature
When a direct middle score is not found, how do we calculate median?
Taking the average of the two middle most scores
Depending on case, the greek symbol sigma is used to indicate ___ or ___
Summation or Standard Deviation (population)
What is the corresponding z score to x=30 if the mean is 20 and the Standard Deviation is 5
2