Question

The results of the test given to students are assume to be normally distributed with a mean of 57 and a standard deviation of 10. The passing score for the exam is 30. Answer in figure only. a) if a student is randomly selected, what is the probability that he or she passed the exam? Answer in 4 decimal places. Answer in percentage in in 2 decimal places. 0.91 b) A score of 75 or greater is needed to obtain an A on the exam. What percentage of the students received an A? Answer in 2 decimal places.

2)

A manufacturer is planning to purchase of a new welder to be used to assemble steel enclosures for products. The size of the weld seam produced by the welder is of interest. The seam widths produced by traditional welding operations have had a mean of 0.15 inch and a standard deviation of 0.010 inch, and the widths are normally distributed. Five trials with the welder produce an average seam width of 0.14 inch. Using a risk level of α = 0.05.

a) What statistic will you use to solve this problem?   
b) What is the value of the statistic? Answer in 2 decimal places.
c) Will you reject the null hypothesis? Answer Yes or No.

3) Dr. Barchard is interested in assessing the Emotional Expressivity of men. Using a sample of 64 men, she found that the mean was 45 and the standard deviation was 16. Calculate a 99% confidence interval for the mean. (use comma to separate the answers, 2 decimal places)

Answer 1

u = 57 stel. deviation lo Passing Score - 30 B P(x230) Plz 30-57 P(x230) = P(Z 7 -2.7) P(2230) - P(2 4-2.7) using 2- Table P(7.-27) 0.0035 P(x230) 1-0.0035 P(430) = 0.9965 Sil Probability of Q student passed يذ 99.65 노 1. or 0.9865 lo 75 P(x>75) P(Z > 75-57 P(X>75) - P(2718) P(X>75) I- P(Za 1.8) 2- table P(Z <118) 0.964) P(x >75) = a 0.0359 osing Som Percentage of grade a is 3.59 of.