4.4,4.5

The average playing time of music albums in a large collection is34minutes, and the standard deviation is3minutes.

(a)

Without assuming anything about the distribution of times, at least what percentage of the times are between28and40minutes?(Round the answer to the nearest whole number.)

(b)

Without assuming anything about the distribution of times, what can be said about the percentage of times that are either less than25minutesor greater than43minutes?(Round the answer to the nearest whole number.)

No more than____%

(c)

Assuming that the distribution of times is approximately normal, about what percentage of times are between28and40minutes?(Round the answers to two decimal places, if needed.)

%

Less than25min or greater than43min?

%

Less than25min?

%