Aand b are two events. p(a)=0.5 , p(b)=0.4 and p(a and b)=0.3 . what is the value of p(a or b) ?

Now, martin can reasonably guess that the standard deviation for the entire population of people at the mall during the time of the survey is $1.50. what is the 95% confidence interval about the sample mean? interpret what this means in the context of the situation where 95 people were surveyed and the sample mean is $8. use the information in this resource to construct the confidence interval.