The following histogram shows the number of miles bryan ran each day in preparation for a half marathon. histogram of miles ran, with number of miles run each day on the x-axis and number of days on the y-axis. there are five bins. they go from 1 to 3, 3 to 5, 5 to 7, 7 to 9, and 9 to 11. the heights of the bins from left to right are 8, 9, 4, 8, and 2. the bar with endpoints 7 and 9 has a height of 8. what does this mean?

Histogram is missing so I created it myself as per given discription.

"They go from 1 to 3, 3 to 5, 5 to 7, 7 to 9, and 9 to 11. "

Means there is interval gap of 2 units along x-axis. which is for number of miles.

"The heights of the bins from left to right are 8, 9, 4, 8, and 2" means height of each bar which represents number of days will go along y-axis as you can see in attached picture.

Now question says "The bar with endpoints 7 and 9 has a height of 8."

You can see that bar is displayed in yellow colour.

along with height of 8 units.

That means on 8th day, Bryan ran between 7 to 9 miles.

In simple words, He ran for some miles between 7 and 9 on 8th day.