You are studying spark plugs in an automobile engine. One aspect of your investigation is the duration of the "spark burn time" (the duration of the spark) while firing. You test a random sample of 27 spark plugs and obtain the data displayed in the following histogram. 5 Frequency 976 984 992 1000 1008 1016 1024 Spark Time (microseconds) Use the histogram above to make the following calculations: Mean: Median: | 1000 Variance: Standard Deviation