Week 3 Flashcards
What are inferential statistics
Used to make inferences (statements/conclusions) about the true state of affairs in the population
What is central tendency
The central tendency of a distribution of scored can be regarded as typical, representative or the middle score in the disctribution
What is dispersion
dispersion means variability i.e., the extent to which a central value can be stretched out or squeezed in or how much a data is likely to vary around an average value. This concept of dispersion in statistics helps in the understanding of the distribution of data.
What is the mean and how is it calculated
Mean in statistics refers to the average of a collection of values. The collection of values can be two or more. The sum of a collection of numbers is divided by the number of numbers in the collection.
What is the mode
The mode is the value that appears most frequently in a data set
What is the median and how is it calculated
The median is the middle number in a sorted, ascending or descending list of numbers and can be more descriptive of that data set than the average. To determine the median value in a sequence of numbers, the numbers must first be sorted, or arranged, in value order from lowest to highest or highest to lowest
What are the features of a normal distribution
Bell shaped curve, symmetrical, has precise mathematical shape
What is the central limit theorem
states that the distribution of a samplevariable approximates a normal distribution (i.e., a “bell curve”) as the sample size becomes larger, assuming that all samples are identical in size, and regardless of the population’s actual distribution shape.
What is a Z score
A Z-score is a numerical measurement that describes a value’s relationship to the mean of a group of values
What does a positive Z score mean
Indicates the score is the above the mean
What does a negative Z score mean
Indicates the score is less than the mean
Why do we need Z scores
Allows for comparison between populations, samples
What is a parameter
A number that describes the data from a population
What is a statistic
A number that describes the data from a sample. Eg means and standard deviations (SD)
What does frequency refer to
The number of times an event occurs
What is experimental relative frequency
The amount of times an event is expected to occur if the experiment was repeated many times
What are nominal variables
Generate frequency data and are used for categorical variables with qualitatively different categories. Eg boys 1, girls 2
What are ordinal vairables
Rank order scales, They have categories that could be ranked ordered along a continuum. Eg rate experience from -10
What are interval variables
Those in which the intervals between adjacent markers are assumed to be equivalent
What are ratio variables
a quantitative variable that can be used to measure a concept on a scale that has a meaningful zero point. For example, if we were interested in measuring the level of economic development in different countries, we could use the ratio variable of Gross Domestic Product (GDP) per capita.
Are interval and ratio variables considered parametric or non-parametric
Parametric
What is the formula to calculate probaility
P= the number of all possible successful outcomes VS the number of all possible outcomes
What is statistical significance
The probability that an obtained statistical value is the result of chance alone
What is the P value
Tells us how likely it is to get a result like this if the hypothesis is true
