According to San Jose Mercury News, children in China average 3 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1 hours and the amount of time spent alone is normally distributed. We randomly survey one Chinese child living in a rural area. 1. Find the probability that the child spends more than 5 hour per day unsupervised. 2. What percent of the children spend less than 2 hours per day unsupervised? We randomly survey 100 Chinese children living in a rural area. 1. What is the chance that the average of unsupervised hour for these 100 children is less than 2.9? 2. What is the chance that the sample average of unsupervised hour for these 100 children is between 2.8 and 3.2 hours?

According to the Centers of Disease Control and Prevention (CDC), the aging of the U.S. population is translating into many more visits to doctors’ offices and hospitals. It is estimated that an average person makes four visits a year to doctors’ offices and hospitals. a. What are the mean and the standard deviation of an average person’s number of monthly visits to doctors’ offices and hospitals? (Round your answers to 4 decimal places.)     b. What is the probability that an average person does not make any monthly visits to doctors’ offices and hospitals? (Do not round intermediate calculations. Round your final answer to 4 decimal places.)     c. What is the probability that an average person makes at least one monthly visit to doctors’ offices and hospitals? (Do not round intermediate calculations. Round your final answer to 4 decimal places.)

A recent study found that 69% of all adults over 50 wear sunglasses for driving. In a random sample of 20 adults over 50, what is the mean and standard deviation of those that wear sunglasses?

A researcher gathered data on five randomly selected individuals from a data set. The ages are 25, 27, 20, 21, and 29. What is the standard deviation for respondent's age?

The average person uses 130 gallons of water daily. If the standard deviation is 35 gallons , find the probability that the mean of a randomly selected sample of 25 people will be between 110 and 135 gallons.Assume the variable is normally distrubuted

1, the mean number of goldfish in the package is 187. find the probability of choosing a package with 147 or more goldfish. 2, Michael Jordan made 83.5% of his free throws for every 200 free throws. find the mean number of free throws made and the standard deviation.

In a survey, 80% of the voters support a particular referendum.  If 30 voters are chosen, find the standard deviation of the number of voters who support the referendum.

60% of all the students passed an exam. If a random sample of 10 students is selected, What is the mean and the standard deviation ?

JA researcher takes an SRS of 80 people who go golfing.The average to be u52 years old. It was also determined that the standard deviation of cac ot golfers was la What is the probability that the sample mean is kss. than 47 years old? age of all golferswas determined years.

Alfie Solomons owns a rum distillery. On average, he produces 100 liters of rum with a standard deviation of 18 liters. What is the probability of producing an average of 90 liters of rum or more over the course of 9 days?