A contractor claims that she finishes a job on time 90% of the time. Last month, she only completed 7 out of her 10 jobs on time. To see if this is surprisingly low, a simulation was conducted 100 times under the assumption that she really does complete 90% of her jobs on time. The dotplot contains 100 trials of this simulation.

A dotplot titled jobs completed on time has number of jobs completed on the x-axis, and frequency on the y-axis. 5, 1; 6, 3; 7, 15; 8, 26; 9, 45; 10, 11.

Based on this dotplot and the sample of last month’s on-time completions, which conclusion can be drawn?

The contractor’s true, on-time completion rate is only 50%.
It is most likely that the contractor will complete about 9 out of 10 jobs.
If we used a larger sample size of 40 jobs, the simulated dotplot would be different; therefore, we cannot draw a conclusion.
The dotplot does not provide convincing evidence that her true, on-time completion rate is less than 90% because 7 or fewer on-time completions happened 19% of the time in the simulation.