You work for a company that sells paint. You have a new machine that fills paint cans, and you have kept track of the mass of 100 cans (units are kilograms) of paint that have been filled by this new machine. You want to investigate whether the mass of the cans is approximately normally distributed.
The mass of each can is displayed in the table below.
3.58 | 3.59 | 3.6 | 3.61 | 3.63 | 3.64 | 3.65 | 3.65 | 3.66 | 3.66 |
3.66 | 3.66 | 3.67 | 3.67 | 3.67 | 3.67 | 3.68 | 3.69 | 3.69 | 3.69 |
3.69 | 3.7 | 3.7 | 3.71 | 3.72 | 3.72 | 3.73 | 3.73 | 3.73 | 3.74 |
3.74 | 3.75 | 3.75 | 3.75 | 3.75 | 3.75 | 3.76 | 3.76 | 3.76 | 3.77 |
3.77 | 3.77 | 3.78 | 3.78 | 3.79 | 3.79 | 3.79 | 3.79 | 3.8 | 3.8 |
3.8 | 3.8 | 3.81 | 3.81 | 3.82 | 3.82 | 3.83 | 3.83 | 3.83 | 3.83 |
3.83 | 3.83 | 3.84 | 3.84 | 3.84 | 3.84 | 3.86 | 3.86 | 3.86 | 3.86 |
3.87 | 3.87 | 3.87 | 3.87 | 3.88 | 3.88 | 3.88 | 3.88 | 3.88 | 3.89 |
3.89 | 3.89 | 3.89 | 3.9 | 3.9 | 3.9 | 3.9 | 3.91 | 3.91 | 3.91 |
3.91 | 3.92 | 3.92 | 3.92 | 3.93 | 3.94 | 3.95 | 3.96 | 3.97 | 4 |
The mean of these 100 cans is 3.794, and the standard deviation is 0.098.
Note that the data has been sorted for you. Count how many of these 100 cans are:
Within 1 standard deviation of the mean:
Within 2 standard deviations of the mean:
Within 3 standard deviations of the mean:
Comment on whether these counts above provide evidence for or against the mass of the cans being approximately normally distributed.
The data analysts created the following plot:
Comment on whether this plot provides evidence for or against the mass of the cans being approximately normally distributed.