Statistics is necessary because scientists and researchers use statistics to draw conclusions from collected data in experiments.
100
What is variability?
Variability is how much change there are in samples.
100
What is A Measure Central Tendency? And explain mean, median, and mode.
What is A Measure Central Tendency? And explain mean, median, and mode.
measure the "middleness" of a distribution of scores in three ways: the mean, median, and mode.
Mean : Average (add up all the numbers and divide by the amount of sample numbers.)
Median: Middle score when listed highest to lowest.
Mode: Most often
100
What is descriptive statistics?
Numerical measures that discribe a distribution by providing information on the central tendency of the distribution, the width of the distribution, and the shape of the distribution.
100
Calculate the mean for the following sample:
3, 4, 7, 9, 33, 0, 5, 5, 8, 9
mean = 8.3
200
What are the 3 goals of science?
The 3 goals of science is to describe, to predict and to explain.
200
What causes variability?
Large amount of different scores. Humans are so different that we need to bring that into account.
200
What do the following symbols represent: x barred, ∑, x, √?
x bar= mean (average)
∑ = Summation
X = a variable
√ = square root
n = the number of variables in a distribution
200
What are the three important aspects to Descriptive Statistics?
Central Tendency
Variability
Shape of Distribution
200
Memory accuracy of males is 75%.
What scale of measurement does this statement best represent?
Ratio Scale
300
What is the Scientific method?
Scientific method is
1. Have a question
2. Make a hypothesis
3. Research
4. Experiment
5. Analyze
6.Draw conclusion from analysis
300
How do you measure variability?
By finding the range. Range is the difference between the largest and smallest number. Ex: 10,15,17,25. 25-10= 15
300
Define the standard deviation?
Shows how consistent scores are. (Small Standard Deviations mean the scores are fairly similar while large Standard Deviations mean the scores are quite different.)
Indicates how well the measures of central tendency decribe the distribution.
300
What is difference between a positively skewed distribution and a negatively skewed distribution?
Positive Skew - the tail of the distribution is towards the left of the distribution
Negative Skew - the tail of the distribution is towards the right of the distribution
300
Calculate the range of the following data set:
3, 4, 7, 9, 33, 0, 5, 5, 8, 9
Range = 33
400
What is the difference between external validity and internal validity
External validity is applicable to the general population.(ex: outside the lab)
Internal validity is when the results are applicable to a controlled experiment. (ex: lab)
400
What is the average deviation from the mean?
x-x! (x bar- average), ( x- basic data)
400
How do you calculate the Standard Deviation of a distribution? (Biased and Unbiased)
s (biased) = √ [x - x(barred)] / n
s (unbiased) = √ [x - x(barred)] / (n - 1)
400
What are the four scales of measurement?
Nominal
Ordinal
Interval
Ratio
Think of the acronym "NOIR" (means black in French)
400
Calculate the Standard Deviation of the following data set (biased and unbiased):
3, 4, 7, 9, 33, 0, 5, 5, 8, 9
Standard Deviation (biased)= 75.01
Standard Devation (unbiased)=83.34
Mean=8.3
Sum=750.1
Sum of all numbers= 83
500
What is the difference between cross-sectional design and longitudinal design?
Cross-sectional design is when you compare different people at different ages only one time.
Longitudinal design is when you follow certain people over a long period of time.
500
What is qualitative and quantitative data?
Qualitative data is nominal data. Quantitative data is ordinal, nominal, interval and ratio.
500
What does "Meu" represent?
The population
500
Define two of the four scales of measurement.
Nominal - naming numbers, each score does NOT represent an amount, used for identification.
Ordinal - scales indicate rank order, not necessarily an EQUAL unit of measurement separating each score.
Interval - each score indicates and actual amount, NO TRUE ZERO, equal unit of measurement seperating two scores.
Ratio - scores reflect the true amount of a variable, equal unit of measurement, and zero truly means that no amount of the variable is present.
500
Calculate the z score for the following data set:
3, 4, 7, 9, 33, 0, 5, 5, 8, 9