4. Mastering a computer program. The number of training units that must be passed before a complex computer soft- ware program is mastered varies from one to five, depend- ing on the student. After much experience, the software manufacturer has determined the probability distribution that describes the fraction of users mastering the software after each number of training units: Number of Units Probability of Mastery 1 .1 2 .25 3 .4 4 .15 5 .1 a. Calculate the mean number of training units necessary to master the program. Calculate the median. Interpret each. b. If the firm wants to ensure that at least 75% of the stu- dents master the program, what is the minimum number of training units that must be administered? At least 90%? c. Suppose the firm develops a new training program that increases the probability that only one unit of training is needed from .1 to .25, increases the probability that only two units are needed to .35, leaves the probability that three units are needed at 4, and completely eliminates the need for four or five units. How do your answers to parts a and b change for this new program?

In a math class, one of your 4 test scores is dropped. On the first three tests, you have the following scores: 78, 35, and 95. What score do you need on the next test for your average to be 75 (assuming you drop the lowest test score)?

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I need help and answer key for 14 and 15

I need to have d, e, and f checked please.

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One third of the cars available for sale in a dealership are used cars. If there are 20 new cars, how many cars are there in the dealership?

I got a few more