A random sample of 16 employees is selected
Please show how you arrived to answers so I can study how you arrived to the answer and explain. thanksQuestions 21 – 25.Time spent during an email session for the employees at Company X is normally distributed with a mean of 9.2 minutes and a standard deviation of 3 minutes.21. The probability is ________ that less than 8 minutes are spent during an email session.22. The probability is ________ that between 7 and 10 minutes are spent during an email session.23. The probability is 0.3 that an email session lasts longer than _______ minutes.24. Almost all (99.7%) of the email sessions last between ______ and ______ minutes25. A random sample of 16 employees is selected. What is the probability that the group’s mean time spent during an email session is greater than 10 minutes?26. The average teacher’s salary in Ohio is $53,309. Assume the population distribution of salaries has a standard deviation of $6,200. If a random sample of 150 Ohio teachers had a mean salary of $54,800, would you be surprised? EXPLAIN.27. In order to answer the previous question, was it necessary to assume that the population had a normal distribution? EXPLAIN.28. The manager of a company is worried about the morale of her employees. In order to determine if a problem in this area exists, she decides to evaluate the attitudes of the employees with a standardized test of job satisfaction which is known to have a normal distribution with a standard deviation of 22 points. How large a sample of employees is needed in order to estimate the mean of all employees using a 99% confidence interval with a length of 6.8 points?29. With 95% confidence, the sample proportion obtained from a sample of 1550 individuals will differ from the true proportion by no more than ______%.[Hint: This question is asking for the margin of error.]30. A quality control engineer is interested in estimating the proportion of defective items coming off a production line. In a sample of 250 items, 27 are defective. A 90% confidence interval for the proportion of defectives from this production line would go from ________ to ________.
