Normal Probability
Please explain solutions for #21, 22.
A final Math exam has a normal distribution with mean 73 and standard deviation 3.5.
21- If one student is randomly selected, find the probability that his score be less than 71:
A) 0.7158 B) 0.2843 C) 0.4934 D) 0.6432
22- If 25 students are randomly selected, find the probability that the mean of their scores be less than 71:
A) 0.9930 B) 0.9979 C) 0.0021 D) 0.0021
23- Why can the Central Limit be applied in question #22, if the sample size doesn't exceed 30?
A) Because the theorem is easy to apply
B) Because the population has a Normal distribution
C) Because this theorem is very important in inferential statistics.
D) Because this theorem apply only in scores distributions.
https://brainmass.com/statistics/probability/probability-distributions-math-exam-scores-414559
Solution Preview
Please see the attachment.
Probability Math Exam
A final Math exam has a normal distribution with mean 73 and standard deviation 3.5.
21- If one student is randomly selected, find the probability that his score be less than 71:
A) 0.7158 B) 0.2843 C) 0.4934 D) ...
Solution Summary
The solution provides step by step method for the calculation of probability using the Z score. Formula for the calculation and Interpretations of the results are also included.