9. The monthly income of 5,000 workers at the Microsoft plant are distributed normally. Suppose the mean monthly income is $1,250 and the standard deviation is $250. . ... 1-ers aorn less +1 - month?. A... d) 97.7% of workers earn less than how much per month? neethelp wit

Which of the following is True about the Z-score of an observation? A. The Z-score of an observation is defined as the number of standard deviations from the mean. B. If the observation is twice as large as the mean, its Z-score is 1. C. The Z-score of an observation is a number between 0 and 1. D. If the observation is right at the mean, its Z-score is 1.

Suppose in 2000, the science scores for female students had a mean of 146 with a standard deviation of 35. Assume that these scores are normally distributed with the given mean and standard deviation.   _________________ of the female students scored between 76 and 216

B Choosing a topic Sk.. For data that is not normally distributed we can't use z-scores. However, there is an equation that works on any distribution. It's called Chebyshev's formula. The formula 1 where p is the minimum percentage of scores that fall within k k2 is p = 1 - standard deviations on both sides of the mean. Use this formula to answer the following questions. a) If you have scores and you don't know if they are normally distributed, find the minimum percentage of scores that fall within 2.2 standard deviations on both sides of the mean? b) If you have scores that are normally distributed, find the percentage of scores that fall within 2.2 standard deviations on both sides of the mean? c) If you have scores and you don't know if they are normally distributed, how many standard deviations on both sides of the mean do we need to go to have 64 percent of the scores? Note: To answer part c you will need to solve the equation for k.

C. Atlantic Video is planning to add the new Marvel movie to their collection, and they predict that this will double their demand (i.e. new arrival rate is 60 customers every hour) and halve the standard deviation of the inter-arrival times. However, they want to keep the average waiting time of customers in line the same as before. Assume that the coefficient of variation for the check-out times does not change. Please answer the following questions.     1) Does the employee need to work twice as fast? If not, calculate the new service rate. 2) What is the average number of customers in the store?