The scores on a college entrance exam have an approximate normal distribution with mean, ,u = 53 points and a standard deviation. 0 = 11 points. Enter the exact answers in increasing order. (a) About 68% of the g values lie between Number and Number , The z-scores are Number and Number , respectively. (b)About 95% of the y values lie between Number and Number , The z-scores are Number and Number , respectively, (c) About 99.7% of the g values lie between Number and Number . The z-soores are Number and Number , respectively, Yoonie is a personnel manager in a large corporation. Each month she must review 14 of the employees. From past experience, she has found that the reviews take her approximately 3.5 hours each to do with a population standard deviation of 1.2 hours. Let X be the random variable representing the time it takes her to complete one review. Assume X is normally distributed. Let f be the random variable representing the mean time to complete the 14 reviews. Assume that the 14 reviews represent a random set of reviews. (a) What is the mean, standard deviation, and sample size? Mean 2 Number Standard Deviation = Number Sample Size = Number (b) Complete the distributions. Round all decimals to four decimal places. XN ctrckrurLlsi - ( Number , Number ) X N Cltcktorbsl - ( Number Number ) The patient recovery time from a particular surgical procedure is normally distributed with a mean of 5.5 day and a standard deviation of 2.1 days. (a) What is the probability of spending more than three days in recovery? An agronomist measured the height of 127 Wheat plants. The mean height was 244 cm and the O 0 8831 deviation was 18 cm Calculate lhe standard error of the mean. 0 0.1169 i l @ 0 10361 O 0 7625 o 1 5912 0 13417 0.1285 0 0 2.7472 (b) The 70"I percentile for recovery times is? LetZ ~ N(D,1).ThenP(Z > a.4) Is 0 6'60 o n 5554 O 6.03 0 03343 0 o 8208 o 3.20 o 0738i 0 4.98 Based on data from the National Health Survey, women between the ages of 18 and 24 have an average systolic blood pressures (in mm Hg) of 112.9 with a standard deviation of 8.84. Systolic blood pressure for women between the ages of 18 to 24 follow a normal distribution. (a) If one woman from this population is randomly selected, nd the probability that her systolic blood pressure is greater than 113. Round your answer to four decimal places. P(z > 113) = Number (b) If 50 women from this population are randomly selected, nd me probability that their mean systolic blood pressure is greater than 113. Round your answer to tour decimal places. PG: > 113) = Number ((2) If the sample were four women between the ages of 18 to 24 and we did not know the original distribution, could the central limit theorem be used? 0 Yes Two thousand students took an exam. The scores on the exam have an approximate normal distribution with a mean it = 79 points and standard deviation 0 = 11 points. Round your answers to one decimal place. (a) Calculate the rst- and third-quartile scores for this exam. Number 7 points to ._. || O a: II Number points (b) The middle 50% of the exam scores are between what two values? Enter your answers in increasing order. The middle 50% of the exam scores are between Number points and Number points. The time to wait for a particular rural bus is distributed uniformly from zero to 74 minutes. 196 riders are randomly sampled to learn how long they waited. (a) The 80'\" percentile sample average wait time (in minutes) for a sample of 196 riders is: 0 518.0 055 as O 35.7 (b) Would you be surprised. based upon numerical calculations, it the sample average wait time (in minutes) for 196 riders was less than 30 minutes? 0 Yes 0 No 0 There is not enough information
