maths studies question of box and whisker plot diagrams

[usernamed]

So basically I was doing a question in my text book and I ended up with my box and whisker plot looking like this...

I was just wondering if it's okay for the arrow to be pointing inwards or whether I have made some kind of mistake in interpreting this question?

Feel free to do the question yourself and see what you end up with.

[usernamed]

So yeah here's the question.

[Emmi]

You've got the right idea, but your box and whiskers plot is wrong. You should be marking five data points on your plot: the minimum, the lower quartile, median, upper quartile, and the maximum value. The median is found by reading off the weight at 50% of the cumulative frequency, which is 100 wrestlers. The upper quartile (the 75% value) is the median between the actual median and the maximum value, and is found by reading off the weight at a cumulative frequency of 75% of the total, which is at 150 wrestlers. The lower quartile (the 25% value) is the median between the minimum value and the actual median and is found by reading off the weight at a cumulative frequency of 25% of the total, which is at 50 wrestlers. The two edges of the box will be the lower and upper quartile values, and the median will fall somewhere between these two quartiles. Then you'll make a mark at the minimum value and draw a line from the minimum value to the lower quartile. The lower quartile value shouldn't be less than the minimum value!

 

I have a median value of about 145, a lower quartile value of 140, and an upper quartile value of about 155.