The average age of our class is 22.3 years.  The standard deviation is 4.7 years.  If the variable is normally distributed:Find the probability a student is between 20 and 30 years old.

The life of light bulbs is distributed normally. The standard deviation of the lifetime is 20 hours and the mean lifetime of a bulb is 580 hours. Find the probability of a bulb lasting for at most 613 hours. Round your answer to four decimal places.

The Orchard Cafe has found that about 14% of the diners who make reservations don't show up. If 82 reservations have been made, how many diners can be expected to show up? Find the standard deviation of this distribution. (Round your answers to two decimal places.) ? =   ? =

Private nonprofit four-year colleges charge, on average, $27,363 per year in tuition and fees. The standard deviation is $6,865. Assume the distribution is normal. Let X be the cost for a randomly selected college. Round all answers to 4 decimal places where possible.b. Find the probability that a randomly selected Private nonprofit four-year college will cost less than 25,876 per year. _________c. Find the 68th percentile for this distribution. $ ________ (Round to the nearest dollar.)   Answer is not - 1. 0.42074 2. 30.475

SAT test scores are normally distributed with a mean of 500 and a standard deviation of 100. Find the probability that a randomly chosen test-taker will score between 430 and 570. (Round your answer to four decimal places.)

Lisa has collected data to find that the number of pages per book on a book shelf has a normal distribution. What is the probability that a randomly selected book has fewer than 137 pages if the mean is 191 pages and the standard deviation is 27 pages? Use the empirical rule. Enter your answer as a percent rounded to two decimal places if necessary.

Cattle are often fattened in a feedlot before being shipped to a slaughterhouse. Suppose the weight gain per steer at a feedlot average 1.75 pounds per day, with a standard deviation of 0.295 pounds. Assume that the weight gain is normal distributed. a. What is the probability a steer will gain over two pounds on a given day? Round your answer the nearest percentage point. Show your work. b. What is the probability that the average weight gain of 25 steers will be less than two pounds on a given day? Show your work. c. What is the probability that in a random sample of 10 steers, more than 5 will gain over two pounds on a given day? Show your work.

Scores on a math test are normally distributed with a mean of 76 and a standard deviation of 6. Part A: Find the probability a student scored between 70 and 58. Round to the nearest hundredth Part B: Find the probability a student scored above a 82. Round to the nearest hundredth

The weights of newborn baby boys born at a local hospital are believed to have a normal distribution with a mean weight of 3331 grams and a variance of 362,404. If a newborn baby boy born at the local hospital is randomly selected, find the probability that the weight will be less than 3812 grams. Round your answer to four decimal places. alt gle. G Answer esc If you would like to look up the value in a table, select the table you want to view, then either click the cell at the intersection of the row and column or use the arrow keys to find the appropriate cell in the table and select it using the Space key. Ⓒ2022 Hawkes Learning 1 1 9 Z 2 W S X # 3 e d C C $ 4 r f % 5 V t g Normal Table-to-z Normal Table - to z 6 b y hp h & 7 n u j 8 O i m ( 9 k O ) O 1 alt 4 Р > Tables : Keypad Keyboard Shortcuts Submit Answer { [ ? Oct 27 11 1 ) 7:2040 backspace 1

Temperatures a city are distributed approximately normal, with a mean of 61 degrees fahrenheit and a standard deviation of 6 degrees Fahrenheit. Find the probability that the city has a temperature lower than 70.5 degrees fahrenheit . Answer with a decimal number , rounded to 4 decimal places .