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Hypothesis Testing

Statistics Problem: Bacteria in Carpeted Rooms

Researchers wanted to determine if carpeted rooms contained more bacteria than uncarpeted rooms. To determine the amount of bacteria in a room, researchers pumped the air from the room over a Petri dish at a rate of 1 cubic foot per minute for eight carpeted rooms and eight uncarpeted rooms. Colonies of bacteria were allowed to

Conducting and Econometrics Analysis

Please see the attached file. An investigator analysing the relationship between food expenditure, disposable income and prices in the US using annual data over the period 1959-83 computes the following regression log(FOOD) = 4.7377 + 0.1069TIME + 0.3506log(PDI) - 0.5086log(PRICE) (0.6805) (0.0033) (0.0899

Statistics Problem Set: Confidence Level

1) For the following sequence: 2,4,7,3,9,4,7,11 find the range, mode, median, mean, IQR, standard deviation, variance and whether it is normally distributed (with explanation) 2) An investor wants to assess at confidence level of 98% if a medicament can improve the marks of students. He notices that for the following daily

Using Statistics to Analyze a Scenario

Scenario: You are interested in researching a new ambulance dispatching method. The new method is supposed to be more efficient and uses half the communications personnel of the old method, saving over $300,000 annually. You want to know how the new method compares to the old method in terms of how many minutes it takes ambulanc

Interpreting the P-Value

In 280 trials with a professional touch therapist, correct responses to a question were obtained 1223 times. The P-value of 0.979 is obtained when testing the claim that p > 0.5 (the proportion of correct responses is greater than the proportion of 0.5 that would be expected with random chance). What is the value of the sample p

SPSS Experimental Analysis - Diet of Rats

See the attached file. A researcher interested in studying the effects of three experimental diets with varying fat contents on the total lipid (fat) level in plasma collected the data in the file FatInDiet.txt. Fifteen male subjects who were within 20 percent of their ideal body weight were grouped into five blocks accor

Statistics Problem: Mean Wait Time

A bank manager has developed a new system to reduce the time customers spend waiting for teller service during peak hours. The manager hopes that the new system will reduce waiting times from the current 9 to 10 minutes to less than 6 minutes. Suppose that the manager wishes to use 100 waiting times to support the claim that th

Hypothesis Testing: Milk Volume Example

Quart cartons of milk should contain at least 32 ounces. A sample of 22 cartons contained the following amounts in ounces. 31.5 32.2 31.9 31.8 31.7 32.1 31.5 31.6 32.4 31.6 31.8 32.2 32.1 32.1 31.6 32.0 31.6 31.7 32.0 31.5 31.9 32.8 a) What set of hypotheses should be tested if we want to demonstrate th

Standard Deviation, Average Number & P-Value Questions

1) The club professional at a difficult public course boasts that his course is so tough that the average golfer loses a dozen or more golf balls during a round of golf. A dubious golfer sets out to show that the pro is fibbing. He asks a random sample of 15 golfers who just completed their rounds to report the number of golf

Baby Birth Weights and Mother Cocaine Use Study

A random sample of the birth weights of 186 babies has a mean of 3103g and a standard deviation of 696g (based on data from "Cognitive Outcomes of Preschool Children with Prenatal Cocaine Exposure," by Singer et al., Journal of the American Medical Association, Vol. 291, No. 20). These babies were born to mothers who did not us

Non-Parametric Test on Software Adoption

Company W is testing a sales software. Their sales force of 500 people is divided into four regions: Northeast, Southeast, Central and West. Each sales person is expected to sell the same amount of products. During the last 3 months, only half of the sales representatives in each region were given the software program to help th

Statistical Testing - T Tests and Proportions

1. Do men and women have different beliefs on the ideal number of children in a family? Based on the following GSS2008 Data and the obtained t statistics, what would you conclude? (0.05) Men Women Mean ideal number of children 3.06

Distribution Analysis: Statistics for Business Textbook Problems

6.8 For each of the following rejection regions, sketch the sampling distribution for z and indicate the location of the rejection region. a. z>1.96 b. z>1.645 c. z>2.575 d. z<-1.28 e. z<-1.645 or z>1.645 f. z<-2575 or z>2.575 g. For each of the rejection regions specified in parts a-f, what is the probability that a Typ

Statistics Variance Problem

We are interested in determining whether or not the variances of the sales at two music stores (A & B) are equal. A sample of 10 days of sales at store A has a standard deviation of 30, while a sample of 16 days of sales from store B has a standard deviation of 20. 1) What is the value of the Observed test statistic? 2) What

"T" Value & Developing a Research Question

Calculate the "t" value for independent groups for the following data using the formula presented in the module. Check the accuracy of your calculations. Using the raw measurement data presented above, determine whether or not there exists a statistically significant difference between the salaries of female and male human resou

Statistical T-Tests for Means

The publisher of Celebrity Living claims that the mean sales for personality magazines that feature people such as Angelina Jolie or Paris Hilton are 1.5 million copies per week. A sample of 10 comparable titles shows a mean weekly sales last week of 1.3 million copies with a standard deviation of 0.9 million million copies. Doe

Testing the Different Performance of Students with and without Sleep

a. Research has shown that losing a few hours of sleep can have a significant effect on performance of some simple tasks. To demonstrate this phenomenon, a sample of n = 25 college students was given a simple problem solving task at noon one day and again at noon on the following day. The students were not permitted any sleep a

Sensitivity and Specificity

Hypertension As part of a study performed in Norway, 70,000 people in the general population had their blood pressure measured; two readings were obtained and the second reading was used in the analysis. The people were followed for mortality outcome over a 10-year period after the blood-pressure measurement using death files

Goodness of Fit Test: Telephone Calls Received

8. During 200 randomly selected minutes, the number of telephone calls received each minute were recorded. At the .05 level of significance, is there any evidence that these data are not Poisson with a mean of 2.8? Number of Calls Per Observed Minute

Statistics: College Writing Scores

State college is evaluating a new english composition course for freshmen. A random sample of N=25 freshmen is obtained and the students are placed in the course during their first semester. One year later, a writing sample is obtained for each student and the writing samples are graded using a standard evaluation technique. The

Research Paper: Major, Age and Gender

Examine the variables in the data file 2004GSS.sav in terms of their labels and values. Develop a research paper with the five sections described below. You should submit your report as one MSWord document with all data and tables copied into that document. Introduction: The purpose of the paper. Rewrite this section after co

Statistics Test Mutual Funds Question

Please help with the following statistics test and mutual funds problems. Step by step calculations are given. Fidelity Magellan is a large cap growth mutual fund and Fidelity Small Cap Stock is a small cap growth mutual fund (Morningstar Funds 500, 2006). The standard deviation for both funds was computed based on a sample

Injuries and Motorcycle Helmet Color

A case-control study was conducted to investigate a relationship between the colors of helmets worn by motorcycle drivers and whether they are injured or killed in a crash. Results are given in the table below. Test the claim that injuries are independent of helmet color. Should motorcycle drivers choose helmets with a particula

Testing a Claim using Significance Testing

Test the given claim - Global warming survey: A Pew research poll was conducted to investigate opinions about global warming. The respondents who answered yes when asked if there is solid evidence that the earth is getting warmer were then asked to select a cause of global warming. The results for two age brackets are give

Statistics Hypothesis Test: Flat Tire

A classic tale involves for carpooling students who missed a test and gave as an excuse a flat tire. On the makeup test, the instructor asked the students to identify the particular tire that went flat. If they really didn't have a flat tire, would they be able to identify the same tire? The author asked 41 other students to ide

Statistics: Heights of Presidential Candidates and Runners-Up

Please help with the following problem. Theories have been developed about the heights of winning candidates for the U.S. presidency and the heights of candidates who were runners-up. Listed below are heights (in inches) from recent presidential elections. Is there a linear correlation between the heights of candidates who w

Testing Hypotheses and T Distribution Statistics

3. An earlier study claims that U.S. adults spend an average of 114 minutes with their families per day. A recently taken sample of 25 adults showed that they spend an average of 109 minutes per day with their families. The sample standard deviation is 11 minutes. Assume that the time spent by adults with their families has an a

Hypothesis Testing Practice Problems

Please see the attachment for proper formatting and symbols. 7.45 #5. Find a value, X0, such that µ = 160 and o2 = 256 a)P(X < X0) = 0.16 b) P(X-< X0) = 0.75 7.64 #16. A sample of size n = 20 is randomly selected from a normal population with mean µ = 90 and standard deviation = 5. Find the following:- a. P (x > 95) t

Statistics: Conclusions for Cobalamine (vitamin B12) in Growing Teens

The recommended daily allowance (RDA) of cobalamine (vitamin B12) for growing teens is 2.4ug (micrograms). It is generally believed that growing teens are getting less than the RDA of 2.4ug of cobalamine daily. The FDA managed to collect with a 24-hour period blood samples of 10 randomly selected teens around the country. The am

Heights of Winners and Runners-Up

Assume that the paired sample data are simple random samples and that the differences have a distribution that is approximately normal. Heights of Winners and Runners-up Listed below are the heights (in inches) of candidates who won presidential elections and the heights of the candidates who were runners up. The data are in