Stats Help for College-level Students

Statistics- Probability

A recent Survey indicated that 18% of America adults were in favor of cloning human embryos. What is the probability that in a group of 30 adult Americans, three or four will be in favor of cloning human embryos? Show your work.

Statistics problem

The director of emergency medicine at NYU hospital is studying patient waiting times. "waiting time" is defined as the time from when a patient enters the facility until he or she is seen by a physician. The study indicates that waiting time follows a normal distribution with a mean of 22 minutes and a standard deviation of 8 mi ...continues

Statistics

The director of emergency medicine at NYU hospital is studying patient waiting times. "waiting time" is defined as the time from when a patient enters the facility until he or she is seen by a physician. The study indicates that waiting time follows a normal distribution with a mean of 22 minutes and a standard deviation of 8 mi ...continues

Working with mean, standard deviation and the normal distribution table.

The average weight of an airline passenger's suitcase is 45 pounds. The standard deviation is 2 pounds. If 15% of the suitcases are overweight, find the maximum weight allowed by the airline. Assume the variable is normally distributed.

Calculating the probability

Assume that the mean systolic blood pressure of normal adults is 120 millimeters of mercury (mm Hg) and the standard deviation is 5.6. Assume the variable is normally distributed. A.) If an individual is selected at random, find the probability that the person's pressure will be between 118 and 121.8mm Hg. B.) If a sample ...continues

Determining if the normal approximation to the binomial distribution should be used.

Determine if the normal approximation to the binomial distribution could be used for the following problems: A.) A study found that 1% of Social Security recipients are too young to vote. 800 Social Security recipients are randomly selected. B.) A study found that 30% of the people in a community use the library in one yea ...continues

Calculating the probability that a mean cost will be less than a specified number given standard deviation.

The average cost of XYZ brand running shoes is $83 per pair, with the standard deviation of $8.00. If 9 pairs of running shoes are selected, find the probability that the mean cost of a pair of shoes will be less than $80. Assume the variable is normally distributed.

Calculating the sample size given a significance level and standard deviation.

A researcher is interested in estimating the average salary of teachers in a large urban school district. She wants to be 95% confident that her estimate is correct. If the standard deviation is $1050, how large a sample is needed to be accurate within $100?

Calculating the true proportion of a group given significance levels and sample size.

A U.S. Travel Data Center survey of 1500 adults found that 42% of respondents stated that they favor historical sites as vacations. Find the 99% confidence interval of the true proportion of adults who favor visiting historical sites as vacations.

Calculating the sample size needed of a true proportion, given significance levels.

A survey of 200 adults showed that 15% played basketball for regular exercise. If a researcher desires to find the 95% confidence interval of the true proportion of adults who play basketball and be within 1% of the true population, how large a sample should be selected?