Probability
What is the definition of probability ?
The chance of something happening or how likely is an event to occur
What is a sample ?
A group of individuals or items that are representative of the population from which they are selected
What is Ho ?
Null Hypothesis
What is a slope (β)?
Measures the average rate of change in the dependent variable (y) for every one unit increase in the independent variable (x).
What is the definition of Confidence Interval ?
A confidence interval is a range of values, calculated from sample data, that is likely to contain the true value of an unknown population parameter
Expressed as a fraction or decimal, this is the probability of an event that is certain to happen
1 or 100%
What is a bias ?
A statistical sampling or testing error caused by systematically favouring some outcomes over others.
What is Ha ?
Alternative Hypothesis
What is a residual plot?
A graph that measures the differences between actual data points a model's predicted values. (Residual = Actual - Predicted).
What does the confidence interval estimate ?
A population parameter.
A dice is rolled. What is the probability that an even number has been obtained?
3/6, 1/2, or 50%
Most basic sampling method, every single member of the population has an equal chance of being chosen, often like drawing names out of a hat.
simple random sampling
Also known as the significance level, symbol
a, alpha
What test(s) do we normally conduct when making an inference about the population regression of a line?
Normally, we conduct either a t-interval test or a confidence test.
Why might a small sample create a less reliable confidence interval?
Because it may not represent the population well.
There are 6 blue marbles, 3 red marbles, and 5 yellow marbles in a bag. What is the probability of selecting a blue or red marble on the first draw?
9/14
A radio show asking listeners to call in and vote on a topic is an example of this type of sampling, which usually attracts people with strong opinions.
Voluntary response sampling
If your calculated p-value is 0.02 and your significance level is 0.05, the appropriate decision to make regarding the null hypothesis is…
we reject the null hypothesis
What are the null and alternative hypothesis when making an inference about the population regression of a line?
Null: There is no association relating x and y. β = 0
Alternative: There is an (or positive/negative) association relating x and y. β≠0, β>0, β<0
Why can confidence intervals not guarantee the exact population mean?
Because they are based on samples, not the full population.
If you flip a coin 5 times, this is the total number of unique sequences of heads and tails that can occur
32
This issue arises when individuals chosen for a survey sample refuse to participate or cannot be contacted, which can heavily skew the data.
Non response bias
To determine a critical value for a t-test, you need the significance level, the direction of the test, and this metric, which is typically calculated as n - 1 for a single sample…
Degrees of freedom
What are the conditions that must be met when making an inference about the population regression of a line?
LINER. L = Linear relationship relating x and y (found in the scatter plot). I = Independent (knowing one outcome does not predict the following result). N = Normal Distribution (found in histogram of residuals). E = Equal S.D (found in residual plot; check for equal amount of points around residual = 0). R = Random (stated in problem).
The margin of error for (40,50) ?
5.