The amount of time taken by a bank teller to serve randomly arriving customers has a normal distribution with a mean of 2.5 minutes and a standard deviation of 30 seconds. (a) For two of the customers, what is the probability that both are served in 2 minute or less? (b) If four customers are served, what is the probability that at least one of them have serving time that exceeds 3 minutes?

A study by the American Heart Association studied the distribution of birth weights for 1295 newborns (preterm babies excluded). They found that the birth weight of human babies is approximately normally distributed with a mean of 7.6 pounds and a standard deviation of 1.09 pounds. (a.) What is the probability that a randomly chosen baby weighs more than 9 pounds at birth? (b.) What is the probability that a randomly chosen baby weights between 6 and 8 pounds at birth? (c.) What is the 80th percentile for birth weight?

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About 71% of all female heart transplant patients will survive for at least 3 years. Eighty female heart transplant patients are randomly selected. What is the probability that the sample proportion surviving for at least 3 years will be pq less than 63%? Assume the sampling distribution of sample proportions is a normal distribution. The mean of the sample proportion is equal to the population proportion and the standard deviation is equal to The probability that the sample proportion surviving for at least 3 years will be less than 63% is (Round to four decimal places as needed.) More Clear All Final Check Help Me Solve This View an Example Get More Help - 4:51 PM 73°F Rain coming 4* 10/4/2021 O Type here to search 10/05/17 EGO PrtSc Insert Delete 口回 F10 F11 F12 F7 F8 F9 F6 Esc F2 F4 F5 F1 F3 & Backspace Num Lock 5 6 2 R T. Y U Home G K L Enter F H. J + |I LEGY P * 00 44 %#3 山

For a standardized psychology examination intended for psychology majors, the historical data show that scores have a mean of 515 and a standard deviation of 175. The grading process of this year's exam has just begun. The average score of the 40 exams graded so far is 518. What is the probability that a sample of 40 exams will have a mean score of 518 or more if the exam scores follow the same distribution as in the past? Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places. Sub Continue

4. Suppose that 60% of college students own a smart phone manufactured by Apple. If a random sample of 200 college students is selected, use the normal distribution to approximate the probability that the number of students in the sample owning a smartphone made by Apple will be less than 105. Is it reasonable to use the normal approximation here?

For a standardized psychology examination intended for psychology majors, the historical data show that scores have a mean of 515 and a standard deviation of 175. The grading process of this year's exam has just begun. The average score of the 35 exams graded so far is 526. What is the probability that a sample of 35 exams will have a mean score of 526 or more if the exam scores follow the same distribution as in the past? Carry your intermediate computations to at least four decimal places: Round your answer to at least three decimal places. Submit Assignment 2021 McGraw Hil LLC. All Rights Reserved. Terms of Use Privacy Center Accessibility US Continue V O 8:19 hp esc 2# 8. 3 4. t 00

A manufacturer knows that their items have a normally distributed length, with a mean of 10 inches, and standard deviation of 3.2 inches.If 3 items are chosen at random, what is the probability that their mean length is less than 12.2 inches?