BackWeighted Mean Michael has just completed his first semester in college. He earned an A in his five-hour calculus course, a B in his four-hour chemistry course, an A in his three-hour speech course, and a C in his three-hour psychology course. Assuming an A equals 4 points, a B equals 3 points, and a C equals 2 points, determine Michael’s grade-point average if grades are weighted by class hours.
Yolanda wishes to develop a new type of meatloaf to sell at her restaurant. She decides to combine 2 pounds of ground sirloin (cost \$2.70 per pound), 1 pound of ground turkey (cost \$1.30 per pound), and 12\frac{1}{2}21 pound of ground pork (cost \$1.80 per pound). What is the cost per pound of the meatloaf?
Suppose the following data represent the amount of time (in hours) a random sample of students enrolled in College Algebra spent working on a homework assignment: 3.2, 4.1, 1.2, 0.6, and 2.5. Below are three bootstrap samples. For each bootstrap sample, determine the bootstrap sample mean.
Bootstrap Sample 1: 1.2, 0.6, 3.2, 3.2, 1.2
Bootstrap Sample 2: 0.6, 4.1, 4.1, 0.6, 4.1
Bootstrap Sample 3: 4.1, 3.2, 3.2, 0.6, 1.2
Download Time A histogram of the download time of a movie, in minutes, for 30 randomly selected movies is shown. The mean download time is 39.007 minutes and the median download time is 39.065 minutes. Identify the shape of the distribution. Which measure of central tendency better describes the “center” of the distribution?
Chicago Taxis Open the data file “ChicagoTaxi”, which is available in StatCrunch. The data file ChicagoTaxi is also available at www.pearsonhighered.com/sullivanstats. This data set represents the trip time, fare, and payment method for all taxi rides on July 25, 2017.
a. Determine the population mean fare of all taxi rides on July 25, 2017.
Travel Time to Work The frequency distribution listed in the table represents the travel time to work (in minutes) for a random sample of 895 U.S. adults.
a. Approximate the mean travel time to work for U.S. adults.
Which Car Would You Buy? Suppose that you are in the market to purchase a car. You have narrowed it down to two choices and will let gas mileage be the deciding factor. You decide to conduct a little experiment in which you put 10 gallons of gas in the car and drive it on a closed track until it runs out gas. You conduct this experiment 15 times on each car and record the number of miles driven. Describe each data set. That is, determine the shape, center, and spread. Which car would you buy and why?
The following data represent the length of time (in minutes) between eruptions of Old Faithful in Yellowstone National Park.
a. Approximate the mean length of time between eruptions. .
The Federal Reserve Bank of St. Louis reported two average personal incomes for 2018: \$33,706 and \$50,731. One of these averages is the mean and the other is the median. Which is the mean? Support your answer.
Why is the median resistant, but the mean is not?
"Putting It Together: Lupus Based on historical birthing records, the proportion of males born worldwide is 0.51. In other words, the commonly held belief that boys are just as likely as girls is false. Systematic lupus erythematosus (SLE), or lupus for short, is a disease in which one’s immune system attacks healthy cells and tissue by mistake. It is well known that lupus tends to exist more in females than in males. Researchers wondered, however, if families with a child who had lupus had a lower ratio of males to females than the general population. If this were true, it would suggest that something happens during conception that causes males to be conceived at a lower rate when the SLE gene is present. To determine if this hypothesis is true, the researchers obtained records of families with a child who had SLE. A total of 23 males and 79 females were found to have SLE. The 23 males with SLE had a total of 23 male siblings and 22 female siblings. The 79 females with SLE had a total of 69 male siblings and 80 female siblings.
c. There are a total of 23+69=92 male siblings in the study. How many female siblings are in the study?
"Kiosks Yolanda opened a new fast food restaurant. From her first customer, Yolanda kept track of the time a patron needed to wait from the time placing the order to the time the customer received his/her order. Because she was unhappy with the wait time, she invested in Kiosks to take orders with the goal of decreasing wait times. In a random sample of 20 customers, it was found the wait time was 52.3 seconds.
b. Determine the mean wait time of the 10,303 customers."
"Birth Weights Suppose birth weights of babies are approximately normal with a mean of 3570 grams and a standard deviation of 495 grams. In a random sample of 15 mothers who were smokers during pregnancy, the mean birth weight of the babies was 3481.6 grams.
b. Simulate obtaining 2000 simple random samples for size n=15 babies from a population that is normally distributed with mean 3570 and standard deviation 495. For each sample, determine the sample mean. Draw a histogram of the 2000 sample means. Explain what each sample mean represents."
[NW] [DATA] TelevisionsIn the Sullivan Statistics Survey I, individuals were asked to disclose the number of televisions in their household. In the following probability distribution, the random variable X represents the number of televisions in households.
c. Calculate and explain the mean of the random variable X.