Probability, Random Variables, and Probability Distributions
What is an advantage of using stratified random sampling over simple random sampling when investigating voter preferences among different age groups?
Requires a smaller overall sample size while maintaining high precision levels.
Provides results that can easily be generalized to other populations without adjustment.
Eliminates bias by including every member from each stratum in the survey.
Ensures proportional representation from each age group for more accurate subgroup analysis.
A jar contains only green and yellow gumballs. If there are twice as many green gumballs as yellow ones, what is the probability that two randomly selected gumballs will both be green?
What is the sample space when tossing a fair coin once?
H;I;HT;TH;TT
I;J;Z;36
H;T
I;Z
In a bag with an equal number of red and blue marbles, two marbles are drawn without replacement; what's the probability that both marbles are red?
If two events A and B are independent, which of the following is true?
A bag contains 6 red, 4 blue, and 5 green marbles; a marble is drawn at random and then replaced before drawing another one; what is the probability of drawing a blue marble both times?
What impact does the presence of outliers have when calculating the standard deviation for use in confidence interval construction and why?
Outliers can significantly increase the calculated standard deviation leading to wider confidence intervals.
Outliers are often excluded, which may result in underestimated standard deviation and misleadingly narrow confidence intervals.
Outliers don't affect the standard deviation since it's a measure of central tendency, not variability.
Outliers typically decrease the calculated standard deviations resulting in narrower confidence intervals.

How are we doing?
Give us your feedback and let us know how we can improve
A jar contains blue and red marbles only; if you have twice as many blue marbles as red ones and you randomly select one marble, what is the expression for calculating the probability that it will be blue?
\frac{12}
\frac{21}
What is the probability of an event occurring if all outcomes in the sample space are equally likely to happen?
The total number of outcomes in the sample space minus the number of outcomes in the event.
The number of outcomes in the event multiplied by the total number of outcomes in the sample space.
The number of outcomes in the event divided by the total number of outcomes in the sample space.
The number of outcomes in the event plus the total number of outcomes in the sample space.
What must the probabilities of all possible outcomes in a sample space add up to?
0
1
10
2
