Arsenic is an element that occurs naturally in groundwater, but a mean greater than 8.0 parts per billion indicates that the groundwater has been contaminated. Local officials are concerned about a well in an area of the city near a factory. On 50 consecutive days, water was randomly sampled from the well. The mean arsenic levels of these 50 measurements was 8.34 ppb with sample standard deviation 0.823 ppb. Is this enough evidence that the groundwater has been contaminated?Below is a histogram and normal quantile/probability plot of the sample values. Match the condition/assumption on the left with the correct description in the context of the problem on the right.

levels 164_ 0.96 1 0.93 128 - 0.9 Normal Quantile Plot 0.84 0.67-0.75 0.6 -0.45 -0.67 0.3 0.18 -12 0.12 0.08 -164- 0.05 0.02 65 7 75 8 85 9 95 10 10.5 Randomization Condition [ Choose] The histogram is unimodal and fairly symmetric. The points in the normal quantile/probability plot are fairly straight. The sample Water was randomly sampled from the well for 50 consecutive days. 10% Condition The sample of 50 days is less than 10% of all days. Nearly Normal Condition [Choose ]