Central Tendency is the most effective way of describing a group of measurement or scores
Mean, Median, Mode are measures of central tendency.
Mean is the center of gravity; sum of all values divided by the no. of values
Use mean when it is distributed symmetrically around central point, greatest stability, and if there is a need to compute for other parameter/statistic
mean in excel - =AVERAGE(values)
median in excel - =MEDIAN(values)
Mean is affected by very high or very low scores
Median is the measure of central tendency and concerned only with the midpoint
The median divides the distributions of scores into two equal parts
Mode is the single measure which occurs most frequently
A quick and approximate measure of central tendency when it is the most typical value
Population is any specific collection of objects of interest
Sample is any subset or subcollection of the population
Measurement attributes to the computed population or sample
Counting and Measuring are two types of measurement
Parameter are the number that summarizes some aspect of population as a whole
Parameter - population
Statistic - sample
Statistics, branch of mathematics that deals with collection, org, analysis and interpretation of numerical data
Inferential statistics - used to make conclusions about populations based on samples
Descriptive statistics - used to describe characteristics of data
Types of Statistics are descriptive, inferential and correlational
Correlational is used to study the reliability and validity
Discrete - can be done by counting
Continuous - gathered by measuring
2 human sources of error are human error & instrument error
Human error is the one who is making the measurements and the one who is taking the measurements.
Instrument error is the accuracy of the instrument used; should be valid & reliable
Significant figures are numbers that are used to express it to the required degree of accuracy
4250 - 3
2080 - 3
30,050. - 5
0.00703 - 3
5030.0 - 5
750,065,080 - 9
370. - 3
10.0 - 3
701.001 - 6
37,000 - 2
Degree of Error is 5%
Importance of statistics for sci works, entertainment, school, business, politics, and sports
Mean (parameter) μ , (statistic) x̄
Variability determines how well you can generalize results and how far points lie
Low v. - idea, better info & population
High v. - values are less consistent & harder to predict
Standard Deviation is the ave. amount of variability in data set
Range is the spread of data from the lowest to highest value
in range, we subtract lowest value from the highest v.
Outliers are extreme values that have a big impact on statistical analyse
variance is the average of squared deviation from mean