About 300 secretaries work in a government agency. Their average keyboard usage rate is 65 words per minute and the standard deviation is 6 words. In order to increase this average, a course is...

About 300 secretaries work in a government agency. Their average keyboard usage rate is 65 words per minute and the standard deviation is 6 words. In order to increase this average, a course is organized for all secretaries. After the course, the keyboard usage speed of a randomly selected group of secretaries among the trainees was found as follows. Has the course had an impact? Indicate which test you did, your results; n, mean and st. deviation, in tabulate. 71 86 77 76 74 60 64 76 73 61 80 75 78 66