Question

The mean attention span for adults in a certain village is 15 minutes with a standard deviation of 6.4. What is the probability of randomly selecting a sample of 30 scores from this population that has a mean attention span equal to or greater than 17 minutes?

Answer 1

All that you need to solve this task is to use basic Z-statistic approach
Start like that
`P(X(BAR) \ \textgreater \ 17)`
Then you have
`Z = X(BAR) - 15 / (6.4/sqrt(30))`
And to complete the task you need to caclulate that with standard table

`P(Z\ \textgreater \ (17-15)/(6.4/sqrt(30))`