Statistical Analysis Flashcards
What do you press to put your calc in stats mode in order to set out the data needed to for pearsons correlation coefficient? (CASIO)
- MODE
- STAT - (2)
- A + Bx - (2)
Once you have plugged your data into a calc what do you press to work out pearsons correlation coefficient? (CASIO)
(Assuming the calc is already in stats mode)
- SHIFT STAT - (1)
- Reg - (5)
- r - (3)
When working out the line of best fit what do you press to reach the 5 values you need? (CASIO)
(Assuming the calc is already in stats mode)
- SHIFT STAT - (1)
- Var - (4)
What formulas do you require to work out the least squares line of best fit and name them in order?
- Gradient
- Y-intercept
What is the gradient formula used to work out the least squares line of best fit equation?
What is the Y-intercept formula used to work out the least squares line of best fit equation?
What is the formula used to work out the least squares line of best fit equation?
(AKA) y = mx + b
What is the meaning of this value - x̅ - used in the calculation of least squares line of best fit?
x̅ is the mean of x scores
What is the meaning of this value - ȳ - used in the calculation of least squares line of best fit?
ȳ is the mean of y scores
What is the meaning of this value - r - used in the calculation of least squares line of best fit?
r is the correlation coefficient
What is the meaning of this value - σx - used in the calculation of least squares line of best fit?
σx is the standard deviation of x scores
What is the meaning of this value - σy - used in the calculation of least squares line of best fit?
σy is the standard deviation of y scores
What is systematic sampling?
A systematic sample is obtained by selecting one person at random and then choosing additional people at evenly spaced intervals.
What is self-selected sampling?
A sample is self-selected when the inclusion or exclusion of people is determined by whether they chose to participate themselves.
What is simple random sampling?
This method occurs when participants are selected from the population at random, free from all bias.
What is stratified sampling?
The population is broken into groups based on one particular characteristic or feature. A stratified sample is then obtained by selecting a simple random sample from each group.
What does the categorical variable ‘ordinal’ mean?
Categorical data whose name does indicate order. E.g movie ratings.
What does the categorical variable ‘nominal’ mean?
Categorical data whose name does not indicate order. E.g gender; male and female.
What is discrete numerical data?
The data obtained when a quantity is counted. It can only take exact numerical values. E.g the number of rooms in a house.
What is continuous numerical data?
Quantitative data that can be measured. It has an infinite number of possible values within a selected range. E.g temperature range.
What is the mode?
The mode of a set of data values is the value that appears most often.
What is the median?
The median is the number in the middle of the data set. To find the median, the data should be arranged in order from least to greatest. If there is an even number of items in the data set, then the median is found by taking the average of the two middle numbers.
What is the range?
The Range is the difference between the lowest and highest values in the data set.
What is the mean?
The mean is the average of the numbers. It is calculated by adding up all the numbers, then dividing by however many numbers there are.
Finish the sentence…
“The symbol ‘μ’ represents the population ? “
The symbol ‘μ’ represents the population mean.
What are the steps taken to calculate the interquartile range?
- Put the numbers in order.
- Make a mark in the centre of the data.
- Find Q1 and Q3 - Q1 is the median (the middle) of the lower half of the data, and Q3 is the median (the middle) of the upper half of the data.
- Subtract Q1 from Q3 - IQR = Q3 - Q1
What is the effect of outliers on summary statistics?
Outliers may skew results. They often have a significant effect on the mean - generally don’t impact the median.