Bessel used personal equations to. A. select the most skillful astronomers. B. demonstrate the value of experimental psychology. C. correct differences in the reaction times among various observers. D. ensure that his assistants had exactly the same reaction times.

The correct option is C) correct differences in the reaction times among various observers

Explanation:

Bessel was an German mathematician and astronomer. He made accurate measurements of the distances between the different stellar objects by using personal equations. Also, Bessel was the scientist who predicted the existence on an 8th planet.

Personalized equations of Bessel were used to correct the various reaction times.

the median of the data is 4.

step-by-step explanation:

the median means the middle number of a given number.

to decide which one is the median, arrange in ascending or descending order. but sometimes, you may find two(2) number in the middle, but it's easy, just add them together and divide by 2.

so,   determine the median of the data. 2, 3, 3, 4, 5, 7, 9

it is already arranged, count 3 times forward and 3 backward and the one left is your answer.

2,3,3,4,5,7,9

our answer is 4.

hope this !

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