Researchers at a medical school want to compare the rates of birth defects in babies born to mothers with low-fat diets with those born to mothers with high-fat diets. For one year, they collected data on all babies and their mothers in area hospitals, using information obtained from the mothers to determine whether they fall in the low fat or high fat diet category. A) Observational B) Experimental

Researchers at a medical school want to compare the rates of birth defects in babies born to mothers with low-fat diets with those born to mothers with high-fat diets. For one year, they collected data on all babies and their mothers in area hospitals, using information obtained from the mothers to determine whether they fall in the low fat or high fat diet category. A) Observational B) Experimental

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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A bank branch located in a commercial district of a city has the business objective of developing an improved process for serving customers during the noon-to-1:00 P.M. lunch period. The waiting time, in minutes, is defined as the time the customer enters the line to when he or she reaches the teller window. Data are collected from a sample of 15 customers during this hour. Another bank branch, located in a residential area, is also concerned with the noon-to-1 P.M. lunch hour. The waiting times, in minutes, are also collected from a sample of 15 customers during this hour. Complete parts (a) through (c) below. The following is the list of time data gathered from the bank branch in the commercial district. 4.55 5.89 3.44 5.03 4.08 2.25 3.65 3.58 4.69 6.03 0.66 5.72 6.17 6.65 3.38 The following is the list of time data gathered from the bank branch in the residential district. 9.44 5.07 8.98 5.13 8.87 3.86…
Consider full-time community college students as an observational unit. a) Come up with one categorical and one quantitative variable related to a full-time community college student. [You CANNOT use AGE, HEIGHT, GENDER, MAJOR]. b) Considering your categorical variable from part a), name three types of graphical displays you can use to represent that variable. c) Come up with one quantitative variable for a community college student that would have a distribution that is SKEWED RIGHT or SKEWED LEFT.
The following is data about the hemoglobin concentrations of volunteers collected at sea level and at an altitude of 11000 feet. sea level concentrations = [14.70 , 15.22, 15.28, 16.58, 15.10 , 15.66, 15.91, 14.41, 14.73, 15.09, 15.62, 14.92]11000 feet concentrations = [14.81, 15.68, 15.57, 16.59, 15.21, 15.69, 16.16, 14.68, 15.09, 15.30 , 16.15, 14.76] There are two alternative scenarios about the way the data were obtained. In scenario 1, there are 12 volunteers who lived for a month at sea level, at which time blood was drawn and the data in "sea level concentrations" dataset were obtained. Subsequently, all 12 volunteers were moved to 11000 ft and after a month the data in the "11000 feet concentrations" dataset obtained. There is a one to one correspondence between the numbers in the two datasets, that is the first numbers correspond to volunteer1, the second numbers to volunteer2 etc. In scenario 2, the "sea level concentrations" dataset is a random sample obtained from 12…
A survey collected data on annual credit card charges in seven different categories of expenditures: transportation, groceries, dining out, household expenses, home furnishings, apparel, and entertainment. Using data from a sample of 42 credit card accounts, assume that each account was used to identify the annual credit card charges for groceries (population 1) and the annual credit card charges for dining out (population 2). Using the difference data, with population 1– population 2, the sample mean difference was d = $870, and the sample standard deviation was s,= $1,125. (a) Formulate the null and alternative hype to test for no difference between the population mean credit card charges for groceries and the population mean credit card charges for dining out. 0> Prt :°H 0 = Pri :ºH O O Ho: Hdso H: H=0 (b) Calculate the test statistic. (Round your answer to three decimal places.) What is the p-value? (Round your answer to four decimal places.) Can you conclude that the population…
As part of a study on transportation safety, the U.S. Department of Transportation collected data on the number of fatal accidents per 1,000 licenses and the percentage of licensed drivers under the age of 21 in a sample of 42 cities. Prepare a managerial report that analyzes the data. Consider the complete data set collected over a one-year period. Safety Percent Under 21 Fatal Accidents per 1000 12 2.942 11 0.688 7 0.865 11 1.632 10 2.071 16 2.607 17 3.81 7 0.348 12 1.122 7 0.625 8 1.008 15 2.781 11 1.385 8 1.413 9 0.019 8 0.318 10 1.829 11 2.226 13 2.835 13 2.332 10 1.274 16 4.08 7 2.17 15 3.603 14 2.603 8 0.815 7 0.8 13 2.87 7 1.247 14 3.204 9 0.994 9 0.473 13 1.423 17 3.594 9 1.906 13 1.623 15 2.923 11 1.893 14 2.794 12 2.614 8 0.906 16 3.236 Find the mean and standard deviation of licensed drivers under the age of 21. (Round your answers to two decimal places.) MeanStandard deviation Find…
A father is concerned that his teenage son is watching too much television each day, since his son watches an average of 2 hours per day His son says that his TV habits are no different than those of his friends. Since this father has taken a stats class, he knows that can actually test to see whether or not his son is watching more TV than his peers The father collects a random sample of watching times from boys at his son's high school and gets the following data: 1.9, 2.3, 2.2, 1.9, 1.6, 2.6, 1.4, 2.0, 2.0, 2.2 Find a 95% confidence interval for the true mean number of hours teenagers at that school watch TV. a. Confidence Interval b. Conclusion
IBL Company manager asked his statistic team to give to the production department the data on the number of phones manufactured over the 17 months.. The data collected are as follows: Months 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 REQUIRED # of phones produced 2045 1566 1207 4563 5052 3465 2542 4134 3567 5163 4563 7453 2621 4772 4563 5052 2846 1. Calculate the following using the data provided on the table: a. the mean b. median c. mode 2. Find the Quartile 1, Quartile 3 and inter-quartile of the phones produced 3. Why is the quartile important? What purpose does it serve? 4. Why is median preferred to mean in certain circumstances? 5. How do we call data when Mode >Median >Mean and show with a diagram how such distribution looks? 6. Explain and compare parameters and statistics.
The article “Well-Fed Crickets Bowl Maidens Over” (Nature Science Update, February 11, 1999) reported that female field crickets are attracted to males with high chirp rates and hypothesized that chirp rate is related to nutritional status. The usual chirp rate for male field crickets was reported to vary around a mean of 60 chirps per second. To investigate whether the chirp rate was related to nutritional status, investigators fed 22 male crickets a high protein diet for 8 days, after which chirp rate was measured. Let: The parameter μμ be the mean chirp rateof male crickets on a high protein diet for 8 days. Given: The mean chirp rate for the random sample of crickets on the high protein diet was reported to be 65.32 chirps per second with a standard deviation of 12. Research Question: Is there convincing evidence that the mean chirp rate for crickets on a high protein diet implies an advantage in attracting the ladies? It is known that the researchers did not want to…
2. [modified from page 76 #3] Coughlin et al. examined the breast and cervical screening practices of Hispanic and non-Hispanic women in counties that approximate the U.S. southern border region. The study used data from the Behavioral Risk Factor Surveillance System surveys of adults age 18 years or older conducted in 1999 and 2000. The table below reports the number of observations of Hispanic and non-Hispanic women who had received a mammogram in the past 2 years cross-classified with marital status. Marital Status Currently Married Divorced or Separated Widowed Never Married or Living As an Unmarried Couple Total Hispanic 319 130 88 41 578 Non-Hispanic 738 329 402 95 1564 Total 1057 459 490 136 2142 a) We select at random a subject who had a mammogram. What is the probability that she is widowed? b) We select at random a subject who had a mammogram and learn that she is Hispanic. With that information, what is the probability that she is married? e) Def two vents in this space that…
As a hospital administrator of a large hospital, you are concerned with the absenteeism among nurses' aides. The issue has been raised by registered nurses, who feel they often have to perform work normally done by their aides. To get the facts, absenteeism data were gathered for the last three weeks, which is considered a representative period for future conditions. After taking random samples of 64 personnel files each day, the following data were produced: Because your assessment of absenteeism is likely to come under careful scrutiny, you would like a type I error of only 1 percent. You want to be sure to identify any instances of unusual absences. If some are present, you will have to explore them on behalf of the registered nurses. a. Design a p-chart. The upper control limit is enter your response here and the lower control limit is enter your response here . (Enter your responses rounded to three decimal places. If your answer for the lower control limit is negative, enter…
The National Highway traffic Safety Administration requires each U.S. state to carry out an observational study to assess the level of seat belt use in the state. One report summarized data from a study done in a certain state. The proportions in the accompanying table are based on observations of over 25,000 drivers and passengers. Male Female Uses Seatbelt Does Not Use Seat Belt 0.42 0.455 0.08 0.045 Assume that these proportions are representative of adults in this state and that an adult from this state is selected at random. (a) What is the probability that the selected adult does not use a seat belt given that the selected individual is female? (b) What is the probability that the selected individual is female given that the selected individual does not use a seat belt? (c) Are the probabilities from parts (a) and (b) equal? Write a couple of sentences explaining why or why not. They --Select--- ✓ equal. Part (a) is the proportion of [---Select--- ---Select--- and part (b) is the…
A study is conducted to compare three new appetite suppressants (A, B, and C) to a placebo in terms of their effect on weight reduction. A total of 80 participants are involved and are randomly assignned to the comparison groups in equal numbers. The outcome of interest is weight reduction, measured in pounds. The data shown in the table below are observed after 3 months on treatment. Is there a significant difference in mean weight reduction among the four treatments? Use a 5% level of significance. (Hint: SST=1889)