Stats Concepts Flashcards
(18 cards)
Calculate the population mean
The symbol is mu. The sum of x divided by the population size.
What is the sample mean?
It is known as x-bar. The sum of x divided by the sample size.
What is the Median?
It is the middle value.
What is the mode?
It is the most frequent value.
How do you know if the sample/population will be a bell-shaped curve or a normal distribution?
When Mean = Median = Mode
When is the distribution positively skewed to the right?
when Mode Mean
When is the distribution negatively skewed to the left?
When Mean
What is the Range?
It is the Max value - Min value
What is the Standard Deviation?
It is the square root of variance.
What is the Empirical Rule?
It applies to bell-shaped curves.
68% of data is within 1 SD of the mean
95% of data is within 2 SD of the mean
99.7% of data is within 3 SD of the mean
What is the equation of Standard Deviation?
s = sum of the quantity of ](x - x-bar)^2 / n-1]
What is a Line Chart?
It is a representation of a trend over time.
What is a Scatter Diagram?
It displays the relationship between two variables.
What is a Bar Chart?
It shows the frequency for each category.
What is a Histogram?
It shows the frequency of each class of measured data
Explain a Box Plot.
It graphically displays based on quartiles, which divides data into 4 parts.
What is a One-Tailed Test?
It is a test when the alternate hypotheses states a direction.
Ex: The mean yearly salaries earned by full-time employees is more than $45,000
H alternative: mu>$45,000
H null: mu
What is a Two-Tailed Test?
It is a test when no direction is specified in the alternate hypothesis.
Ex: The mean amount of time spent for the internet is not equal to 5 hours.
H
