# Normal Probabilities and Confidence Interval

Use the Student_Data.xls file which consists of 200 MBA students at Whatsamattu U. The file includes variables regarding students' age, gender, major, GPA, Bachelors GPA, course load, English speaking status, family, weekly hours spent studying. Each of the three assigned problems should be formatted as a one page memo. Answers to all three of the problems should be submitted via the Drop Box as a single Word document with each of the problems clearly labeled. Be sure to include your name on the document itself!

COMPLETE PROBLEM 1: Let's assume (for this problem only) that the Student_Data.xls file was the entire population. We know the mean and standard deviation of student ages to be 42.3 and 8.9, respectively. Using the Normal_ Probability.xls file:

a) compute the percentage of students that are older than 50,

b) compute the percentage of students that are younger than 40,

c) compute the percentage of students that are between 41 and 46, inclusive.

d) compute the age range of the oldest 10% of the students.

Then compare each of the answers you computed to the truth as found in the actual file. Briefly discuss your results (100+ words, 3 or more sentences).

COMPLETE PROBLEM 2: You wish to know the average GPA of MBA students at Whatsamatta U. Compute the 95% confidence interval of the mean using the sample of 200 students. Report on your findings (50+ words, 2 or more sentences) along with a normal probability chart that illustrates the points raised in your report.

COMPLETE PROBLEM 3: You wish to know the proportion of MBA students that are majoring in Finance. Compute the 95% confidence interval of the proportion using the sample of 200 students. Report on your findings (50+ words, 2 or more sentences) along with a normal probability chart that illustrates the points raised in your report.

#### Solution Summary

The solution provides step by step method for the calculation of probability using the Z score and confidence interval. Formula for the calculation and Interpretations of the results are also included.