Annual starting salaries for college graduates with business administration degrees are believed to have a standard deviation of approximately $2000.  Assume that a 95% confidence interval estimate of the mean annual salary is desired.  How large a sample should be taken if the desired margin is $500, $200, or $100?

Suppose the durations of human pregnancies follow a mound-shaped distribution with a mean of 266 days and a standard deviation of 18 days. a. Approximately what percentage of human pregnancies last between 248 and 284 days?  b. Between what two values will the durations of 95% of all human pregnancies fall? Answer in days

It is known that incomes from the USA follow a normal distribution with a mean of $55,000 and a standard deviation of $12,000.  A researcher took a sample of 100 people in the USA and obtained a sample mean of $67,000 with a standard deviation of $18,000.  What are the characteristics of the sampling distribution. A. Mean = $55,000 and Standard Deviation of the Mean = $1200 B. Mean = $55,000 and Standard Deviation of the Mean = $12000 C. Mean = $67,000 and Standard Deviation of the Mean = $569.21 D. Mean = $67,000 and Standard Deviation of the Mean = $1800

Newborn babies: A study conducted by the Center for Population Economics at the University of Chicago studied the birth weights of 716 babies born in New York. The mean weight was 3506 grams with a standard deviation of 868 grams. Assume that birth weight data are approximately bell-shaped. Estimate the number of newborns who weighed between 1770 grams and 5242 grams. Round to the nearest whole number. The number of newborns who weighed between 1770 grams and 5242 grams is

The typical amount of sleep per night for college graduate students has a normal distribution with a mean of 5 hours. What is the standard deviation of this distribution if ​16% of students sleep more than 6.5​ hours?   A. ​-1.52   B. ​-1.55   C. 1.52   D. 1.55

Entrance exam scores at Cititon University are normally distributed with a mean of 552 and a standard deviation of 29. If scholarships are awarded to the top 10% of scores, what is the minimum score needed to guarantee a scholarship?

The Human Development Report 2013, published by the United Nations, showed life expectancies by country. Values reported for some countries in Western Europe and values reported for some countries in Africa are available in the accompanying table. a. Which group (Western Europe or Africa) of life expectancies do you think has the larger standard deviation? Why? b. Find the standard deviation for each group. Compare them to illustrate that s is larger for the group that shows more variability from the mean. Click the icon to view the life expectancy data. X Life Expectancy Data a. Which group do you think has the larger standard devia European Country Austria O A. The Africa group should have the larger standard d O B. The Western Europe group should have the larger OC. The Western Europe group should have the larger O D. The Africa group should have the larger standard d Life Expectancy African Country 81 Angola Botswana 80 80 Belgium Denmark Finland France 81 83 81 standard deviation…

Suppose there is a city where the mean cost per month of a one-bedroom apartment is $1,500, with a standard deviation of $250. Approximately what percentage of one-bedroom apartments in the city cost between $750 and $1,000?

A successful basketball player has a height of 6 feet 11 ​inches, or 211 cm. Based on statistics from a data​ set, his height converts to the z score of 5.17. How many standard deviations is his height above the​ mean?

According to Chebyshev's Rule, at least what percent of observations must be within 2.5 standard deviations from the mean?  [a]%