It would be helpful for you to attach a jpg of png image of your graph instead of a Powerpoint slide. You also can’t attach the raw .ino file to forum posts, but you can cut and paste it using the “code” tags in the post editor tools.
And on your graph, can you please label both the x and y-axis? I don’t know what parameter you’re graphing and on what time scale your measurements covered. I’m assuming your graph shows either temperature or soil moisture. How were you testing the sensor? Was is installed outside or in a controlled environment? What kind of results were you expecting and what makes you think something is inconsistent?